First 4 Riesel conjectures
For the original Riesel problem, it is finding and proving the smallest k such that k×bn-1 is not prime for all integers n ≥ 1 and GCD(k-1, b-1)=1.
Finding and proving the smallest k such that (k×bn-1)/GCD(k-1, b-1) is not prime for all integers n ≥ 1.
All n must be >= 1.
k-values that make a full covering set with all or partial algebraic factors are excluded from the conjectures.
k-values that are a multiple of base (b) and where (k-1)/gcd(k-1,b-1) is not prime are included in the conjectures but excluded from testing.
Such k-values will have the same prime as k / b.
Base | Conjectured first 4 Riesel k | k's that make a full covering set with all or partial algebraic factors | Remaining k to find prime (n testing limit) | Top 10 k's with largest first primes: k (n) (sorted by n only) | Comments |
4 | 361, 919, 1114, 1444 | All k = m^2 for all n; factors to: (m*2^n - 1) * (m*2^n + 1) | none - proven | 659 (400258) 1211 (12621) 751 (6615) 674 (5838) 1159 (5628) 106 (4553) 1189 (3404) 1171 (2855) 373 (2508) 1103 (2203) | k = 1^2, 2^2, 3^2, 4^2, 5^2, 6^2, 7^2, 8^2, 9^2, 10^2, 11^2, 12^2, 13^2, 14^2, 15^2, 16^2, etc. (except 19^2) proven composite by full algebraic factors. |
5 | 13, 17, 37, 41 | none - proven | 34 (163) 38 (28) 32 (8) 31 (5) 35 (4) 26 (4) 23 (4) 2 (4) 1 (3) 29 (2) | ||
7 | 457, 1291, 3199, 3313 | 679, 691, 717, 859, 919, 1031, 1179, 1459, 1651, 1679, 1693, 1747, 1811, 1831, 1873, 1979, 2011, 2131, 2137, 2253, 2311, 2623, 2673, 2791, 2797, 2839, 2887, 3139, 3181, 3217, 3307 (k = 1 mod 6 at n=3K, other k at n=15K) | 197 (181761) 367 (15118) 313 (5907) 1793 (5839) 159 (4896) 1469 (4669) 429 (3815) 3033 (2819) 2473 (2779) 2493 (2567) | ||
8 | 14, 112, 116, 148 | All k = m^3 for all n; factors to: (m*2^n - 1) * (m^2*4^n + m*2^n + 1) | none - proven | 74 (2632) 37 (851) 142 (463) 73 (389) 92 (314) 127 (139) 104 (96) 47 (26) 84 (24) 43 (21) | k = 1, 8, 27, 64, and 125 proven composite by full algebraic factors. |
9 | 41, 49, 74, 121 | All k = m^2 for all n; factors to: (m*3^n - 1) * (m*3^n + 1) | none - proven | 119 (4486) 53 (536) 71 (23) 87 (15) 94 (12) 11 (11) 107 (9) 89 (8) 24 (8) 14 (8) | k = 1, 4, 9, 16, 25, 36, 64, 81, and 100 proven composite by full algebraic factors. |
10 | 334, 1585, 1882, 3340 | k = 343: n = = 1 mod 3: factor of 3 n = = 2 mod 3: factor of 37 n = = 0 mod 3: let n=3q; factors to: (7*10^q - 1) * [49*10^(2q) + 7*10^q + 1] | 2452 (554.7K) | 1935 (51836) 1803 (45882) 1231 (37398) 1343 (29711) 505 (18470) 450 (11958) 3112 (3292) 1198 (2890) 2276 (2726) 2333 (2113) | |
11 | 5, 7, 17, 19 | none - proven | 1 (17) 9 (5) 16 (3) 15 (2) 14 (2) 8 (2) 3 (2) 2 (2) 18 (1) 13 (1) | ||
12 | 376, 742, 1288, 1364 | (Condition 1): All k where k = m^2 and m = = 5 or 8 mod 13: for even n let k = m^2 and let n = 2*q; factors to: (m*12^q - 1) * (m*12^q + 1) odd n: factor of 13 (Condition 2): All k where k = 3*m^2 and m = = 3 or 10 mod 13: even n: factor of 13 for odd n let k = 3*m^2 and let n=2*q-1; factors to: [m*2^(2q-1)*3^q - 1] * [m*2^(2q-1)*3^q + 1] | none - proven | 1132 (28717) 1037 (6281) 298 (1676) 1119 (1351) 1262 (1017) 534 (781) 844 (744) 943 (676) 647 (545) 831 (318) | k = 25, 64, 324, 441, 961, and 1156 proven composite by condition 1. k = 27, 300, and 768 proven composite by condition 2. |
13 | 29, 41, 69, 85 | none - proven | 43 (77) 76 (34) 52 (18) 25 (15) 28 (14) 20 (10) 34 (8) 72 (6) 47 (6) 42 (6) | ||
14 | 4, 11, 19, 26 | All k where k = m^2 and m = = 2 or 3 mod 5: for even n let k = m^2 and let n = 2*q; factors to: (m*14^q - 1) * (m*14^q + 1) odd n: factor of 5 | none - proven | 5 (19698) 2 (4) 1 (3) 24 (2) 23 (2) 20 (2) 17 (2) 15 (2) 8 (2) 25 (1) | k = 9 proven composite by partial algebraic factors. |
16 | 100, 172, 211, 295 | All k = m^2 for all n; factors to: (m*4^n - 1) * (m*4^n + 1) | none - proven | 74 (638) 137 (545) 178 (276) 148 (266) 273 (245) 219 (103) 152 (98) 235 (68) 203 (58) 263 (45) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 121, 144, 169, 196, 225, 256, and 289 proven composite by full algebraic factors. |
17 | 49, 59, 65, 86 | All k where k = m^2 and m = = 7 or 9 mod 16: for even n let k = m^2 and let n = 2*q; factors to: (m*17^q - 1) * (m*17^q + 1) odd n: factor of 2 | none - proven | 44 (6488) 29 (4904) 13 (1123) 36 (243) 10 (117) 26 (110) 5 (60) 11 (46) 58 (35) 46 (25) | k = 81 proven composite by partial algebraic factors. |
18 | 246, 664, 723, 837 | 533, 597 (both at n=3K) | 324 (25665) 628 (2213) 474 (1316) 457 (951) 501 (481) 337 (452) 151 (418) 811 (409) 711 (354) 261 (347) | ||
19 | 9, 11, 29, 31 | All k where k = m^2 and m = = 2 or 3 mod 5: for even n let k = m^2 and let n = 2*q; factors to: (m*19^q - 1) * (m*19^q + 1) odd n: factor of 5 | none - proven | 23 (108) 1 (19) 18 (6) 14 (6) 17 (5) 27 (4) 26 (3) 24 (2) 15 (2) 10 (2) | k = 4 proven composite by partial algebraic factors. |
20 | 8, 13, 29, 34 | none - proven | 17 (22) 15 (21) 2 (10) 16 (9) 11 (8) 14 (6) 28 (3) 1 (3) 32 (2) 27 (2) | ||
21 | 45, 65, 133, 153 | none - proven | 64 (2867) 131 (222) 101 (144) 47 (98) 29 (98) 84 (88) 142 (48) 109 (48) 61 (36) 77 (20) | ||
23 | 5, 7, 17, 19 | none - proven | 14 (52) 3 (6) 2 (6) 4 (5) 1 (5) 18 (2) 15 (2) 12 (2) 11 (2) 8 (2) | ||
25 | 105, 129, 211, 313 | All k = m^2 for all n; factors to: (m*5^n - 1) * (m*5^n + 1) | 181, 235 (both at n=3K) | 86 (1029) 268 (237) 177 (87) 274 (83) 170 (81) 137 (76) 265 (54) 58 (26) 272 (24) 130 (24) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, and 289 proven composite by full algebraic factors. |
26 | 149, 334, 1892, 1987 | 178, 191, 223, 254, 284, 317, 355, 368, 380, 454, 562, 628, 729, 874, 892, 898, 926, 1061, 1147, 1153, 1157, 1184, 1189, 1204, 1208, 1214, 1279, 1312, 1375, 1376, 1541, 1549, 1657, 1736, 1774, 1852, 1901, 1930, 1934, 1945, 1963 (all at n=3K) | 115 (520277) 32 (9812) 1094 (2586) 1186 (2541) 1237 (2277) 913 (1913) 1514 (1638) 121 (1509) 1704 (1486) 410 (1308) | ||
27 | 13, 15, 41, 43 | All k = m^3 for all n; factors to: (m*3^n - 1) * (m^2*9^n + m*3^n + 1) | none - proven | 23 (3742) 9 (23) 29 (13) 11 (10) 39 (8) 34 (8) 20 (8) 19 (8) 33 (7) 42 (5) | k = 1, 8, and 27 proven composite by full algebraic factors. |
29 | 4, 9, 11, 13 | none - proven | 2 (136) 8 (38) 1 (5) 10 (3) 5 (2) 12 (1) 7 (1) 6 (1) 3 (1) | ||
31 | 145, 265, 443, 493 | 5, 19, 51, 73, 97, 179, 191, 223, 235, 239, 247, 259, 274, 415, 421, 463, 467, 487, 489 (all at n=3K) | 401 (2977) 123 (1872) 313 (1605) 209 (1589) 214 (1143) 124 (1116) 113 (643) 49 (637) 115 (464) 391 (378) | ||
32 | 10, 23, 43, 56 | All k = m^5 for all n; factors to: (m*2^n - 1) * (m^4*16^n + m^3*8^n + m^2*4^n + m*2^n + 1) | 29 (2M) | 37 (6425) 13 (159) 44 (72) 26 (58) 54 (24) 39 (21) 47 (14) 3 (11) 53 (10) 42 (10) | k = 1 and 32 proven composite by full algebraic factors. |
33 | 545, 577, 764, 1633 | (Condition 1): All k where k = m^2 and m = = 4 or 13 mod 17: for even n let k = m^2 and let n = 2*q; factors to: (m*33^q - 1) * (m*33^q + 1) odd n: factor of 17 (Condition 2): All k where k = 33*m^2 and m = = 4 or 13 mod 17: [Reverse condition 1] (Condition 3): All k where k = m^2 and m = = 15 or 17 mod 32: for even n let k = m^2 and let n = 2*q; factors to: (m*33^q - 1) * (m*33^q + 1) odd n: factor of 2 | 257, 339, 817, 851, 951, 1123, 1240 (k = 257 and 339 at n=12K, other k at n=3K) | 732 (19011) 186 (16770) 254 (3112) 562 (3087) 1408 (2920) 1157 (2647) 142 (2568) 1327 (1691) 1582 (1651) 370 (1628) | k = 16, 169, 441, 900, and 1444 proven composite by condition 1. k = 528 proven composite by condition 2. k = 225 and 289 proven composite by condition 3. |
34 | 6, 29, 41, 64 | none - proven | 27 (3086) 31 (75) 44 (36) 59 (34) 57 (23) 33 (15) 1 (13) 20 (10) 22 (5) 21 (5) | ||
35 | 5, 7, 17, 19 | none - proven | 1 (313) 3 (6) 2 (6) 16 (5) 14 (4) 8 (4) 15 (2) 11 (2) 6 (2) 18 (1) | ||
37 | 29, 77, 113, 163 | 33, 149 (k = 33 at n=10K, k = 149 at n=3K) | 81 (7683) 162 (1450) 56 (1158) 5 (900) 101 (574) 92 (313) 109 (188) 130 (146) 100 (99) 141 (74) | ||
38 | 13, 14, 25, 53 | 44 (3K) | 37 (136211) 22 (1579) 11 (766) 9 (43) 19 (41) 41 (26) 27 (23) 50 (16) 31 (15) 33 (9) | ||
39 | 9, 11, 29, 31 | All k where k = m^2 and m = = 2 or 3 mod 5: for even n let k = m^2 and let n = 2*q; factors to: (m*39^q - 1) * (m*39^q + 1) odd n: factor of 5 | none - proven | 1 (349) 14 (100) 24 (94) 16 (35) 30 (8) 15 (4) 13 (3) 27 (2) 23 (2) 19 (2) | k = 4 proven composite by partial algebraic factors. |
41 | 8, 13, 17, 25 | none - proven | 14 (212) 7 (153) 5 (10) 23 (6) 18 (4) 11 (4) 22 (3) 1 (3) 20 (2) 6 (2) | ||
43 | 21, 23, 65, 67 | 13, 55 (k = 13 at n=50K, k = 55 at n=3K) | 53 (301) 4 (279) 35 (204) 12 (203) 61 (87) 17 (79) 59 (76) 39 (40) 31 (38) 3 (24) | ||
44 | 4, 11, 19, 26 | none - proven | 23 (18) 8 (16) 24 (14) 20 (12) 16 (9) 12 (5) 1 (5) 2 (4) 25 (3) 21 (3) | ||
45 | 93, 137, 277, 321 | 197, 257 (both at n=3K) | 24 (153355) 53 (582) 286 (211) 205 (174) 70 (167) 313 (165) 106 (161) 102 (160) 29 (146) 204 (141) | ||
47 | 5, 7, 13, 14 | none - proven | 4 (1555) 1 (127) 10 (51) 8 (32) 2 (4) 11 (2) 3 (2) 12 (1) 9 (1) 6 (1) | ||
49 | 81, 129, 229, 241 | All k = m^2 for all n; factors to: (m*7^n - 1) * (m*7^n + 1) | 82 (10K) | 230 (24824) 194 (2530) 159 (2448) 139 (234) 79 (212) 115 (128) 216 (125) 44 (122) 106 (69) 209 (64) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, and 225 proven composite by full algebraic factors. |
50 | 16, 35, 67, 86 | (Condition 1): All k where k = m^2 and m = = 4 or 13 mod 17: for even n let k = m^2 and let n = 2*q; factors to: (m*50^q - 1) * (m*50^q + 1) odd n: factor of 17 (Condition 2): All k where k = 2*m^2 and m = = 3 or 14 mod 17: even n: factor of 17 for odd n let k = 2*m^2 and let n=2*q-1; factors to: [m*5^(2q-1)*2^q - 1] * [m*5^(2q-1)*2^q + 1] | 37, 68 (k = 37 at n=121K, k = 68 at n=3K) | 76 (1049) 14 (66) 49 (25) 73 (19) 52 (19) 13 (19) 84 (12) 5 (12) 75 (11) 44 (8) | No k's proven composite by condition 1. k = 18 proven composite by condition 2. |
51 | 25, 27, 77, 79 | All k where k = m^2 and m = = 5 or 8 mod 13: for even n let k = m^2 and let n = 2*q; factors to: (m*51^q - 1) * (m*51^q + 1) odd n: factor of 13 | none - proven | 1 (4229) 23 (96) 47 (40) 74 (23) 45 (21) 75 (10) 53 (9) 62 (8) 39 (8) 3 (8) | k = 64 proven composite by partial algebraic factors. |
53 | 13, 17, 37, 41 | none - proven | 33 (1877) 22 (211) 12 (71) 10 (71) 2 (44) 29 (40) 26 (30) 38 (24) 14 (20) 16 (15) | ||
54 | 21, 34, 76, 89 | (Condition 1): All k where k = m^2 and m = = 2 or 3 mod 5: for even n let k = m^2 and let n = 2*q; factors to: (m*54^q - 1) * (m*54^q + 1) odd n: factor of 5 (Condition 2): All k where k = 6*m^2 and m = = 1 or 4 mod 5: even n: factor of 5 for odd n let k = 6*m^2 and let n=2*q-1; factors to: [m*2^q*3^(3q-1) - 1] * [m*2^q*3^(3q-1) + 1] | 45 (3K) | 32 (1044) 87 (310) 23 (267) 59 (200) 82 (48) 46 (43) 26 (37) 79 (34) 44 (22) 72 (19) | k = 4, 9, 49, and 64 proven composite by condition 1. k = 6 proven composite by condition 2. |
55 | 13, 15, 41, 43 | none - proven | 3 (76) 22 (21) 1 (17) 27 (8) 11 (8) 23 (6) 20 (6) 39 (4) 19 (4) 9 (3) | ||
56 | 20, 37, 77, 94 | 43 (3K) | 59 (276) 83 (238) 76 (211) 29 (108) 65 (66) 74 (64) 36 (45) 38 (38) 26 (32) 88 (29) | ||
57 | 144, 177, 233, 289 | All k where k = m^2 and m = = 3 or 5 mod 8: for even n let k = m^2 and let n = 2*q; factors to: (m*57^q - 1) * (m*57^q + 1) odd n: factor of 2 | none - proven (with probable primes that have not been certified: k = 281) | 281 (5610) 242 (1188) 87 (242) 262 (241) 278 (184) 204 (163) 54 (157) 201 (138) 173 (112) 100 (109) | k = 9, 25, 121, and 169 proven composite by partial algebraic factors. |
59 | 4, 5, 7, 9 | none - proven | 3 (8) 1 (3) 8 (2) 2 (2) 6 (1) | ||
61 | 125, 185, 373, 433 | 37, 53, 100, 139, 165, 229, 313, 353, 365, 389, 421 (k < 125 at n=10K, k > 125 at n=3K) | 198 (41855) 404 (18637) 13 (4134) 77 (3080) 131 (2464) 430 (2248) 10 (1552) 406 (1289) 156 (1049) 41 (755) | ||
62 | 8, 13, 29, 34 | 22, 26 (both at n=3K) | 14 (80) 3 (59) 28 (51) 4 (9) 17 (6) 19 (5) 20 (4) 31 (3) 1 (3) 33 (2) | ||
64 | 14, 51, 79, 116 | All k = m^2 for all n; factors to: (m*8^n - 1) * (m*8^n + 1) -or- All k = m^3 for all n; factors to: (m*4^n - 1) * (m^2*16^n + m*4^n + 1) | none - proven | 24 (3020) 74 (1316) 106 (263) 92 (157) 99 (122) 69 (90) 104 (48) 85 (26) 47 (13) 84 (12) | k = 1, 4, 8, 9, 16, 25, 27, 36, 49, 64, 81, and 100 proven composite by full algebraic factors. |
81 | 74, 575, 657, 737 | All k = m^2 for all n; factors to: (m*9^n - 1) * (m*9^n + 1) | 123, 302, 477, 478, 630, 698, 716, 731 (all at n=3K) | 581 (2403) 119 (2243) 487 (1405) 366 (1388) 443 (995) 513 (873) 241 (600) 327 (492) 546 (429) 662 (403) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, and 729 proven composite by full algebraic factors. |
100 | 211, 235, 334, 750 | (Condition 1): All k = m^2 for all n; factors to: (m*10^n - 1) * (m*10^n + 1) (Condition 2): k = 343: n = = 1 mod 3: factor of 37 n = = 2 mod 3: factor of 3 n = = 0 mod 3: let n=3q; factors to: (7*100^q - 1) * [49*100^(2q) + 7*10^q + 1] | none - proven (with probable primes that have not been certified: k = 133, 469, and 505) | 653 (717513) 74 (44709) 505 (9235) 450 (5979) 133 (5496) 469 (4451) 302 (2132) 470 (1957) 630 (1691) 690 (1310) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, and 729 proven composite by condition 1. k = 343 proven composite by condition 2. |
128 | 44, 59, 85, 86 | All k = m^7 for all n; factors to: (m*2^n - 1) * (m^6*64^n + m^5*32^n + m^4*16^n + m^3*8^n + m^2*4^n + m*2^n + 1) | 46 (142.857K) | 29 (211192) 62 (44484) 23 (2118) 26 (1442) 74 (1128) 76 (759) 37 (699) 16 (459) 42 (246) 72 (124) | |
256 | 100, 172, 211, 295 | All k = m^2 for all n; factors to: (m*16^n - 1) * (m*16^n + 1) | 191, 261, 286 (all at n=3K) | 242 (37762) 262 (1856) 282 (948) 219 (471) 247 (336) 74 (319) 47 (228) 42 (224) 274 (148) 92 (143) | k = 1, 4, 9, 16, 25, 36, 49, 64, 81, 121, 144, 169, 196, 225, 256, and 289 proven composite by full algebraic factors. |
512 | 14, 20, 37, 38 | All k = m^3 for all n; factors to: (m*8^n - 1) * (m^2*64^n + m*8^n + 1) | none - proven | 26 (3290) 4 (2215) 13 (2119) 24 (1655) 32 (472) 31 (93) 34 (51) 33 (40) 35 (34) 19 (21) | k = 1, 8, and 27 proven composite by full algebraic factors. |
1024 | 81, 121, 124, 169 | All k = m^2 for all n; factors to: (m*32^n - 1) * (m*32^n + 1) -or- All k = m^5 for all n; factors to: (m*4^n - 1) * (m^4*256^n + m^3*64^n + m^2*16^n + m*4^n + 1) | 29, 31, 56, 61, 84, 91, 106, 109, 116, 136, 157, 166 (k = 29 at n=1M, other k at n=3K) | 74 (666084) 39 (4070) 43 (2290) 99 (1226) 13 (1167) 151 (639) 78 (424) 105 (281) 114 (276) 137 (218) | k = 1, 4, 9, 16, 25, 32, 36, 49, 64, 100, and 144 proven composite by full algebraic factors. |