First 4 Sierpinski 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 | 419, 659, 794, 1466 | 1238, 1286 (both at n=3K) | 186 (10458) 766 (3196) 839 (1217) 1194 (1075) 1206 (590) 1221 (586) 1301 (574) 1201 (480) 857 (471) 1154 (449) | ||
5 | 7, 11, 31, 35 | none - proven | 34 (8) 27 (4) 22 (4) 19 (4) 32 (3) 18 (3) 28 (2) 25 (2) 24 (2) 16 (2) | ||
7 | 209, 1463, 3305, 3533 | 389, 443, 563, 569, 687, 689, 827, 1009, 1049, 1101, 1467, 1511, 1604, 1627, 1787, 1789, 2083, 2089, 2183, 2369, 2401, 2441, 2507, 2627, 2663, 2867, 2921, 3047, 3209, 3289, 3428, 3489 (all at n=3K) | 2786 (2853) 2801 (2688) 1775 (2625) 1921 (2556) 429 (2362) 3503 (2337) 1087 (2331) 1367 (2267) 1927 (2147) 863 (1985) | ||
8 | 47, 79, 83, 181 | All k = m^3 for all n; factors to: (m*2^n - 1) * (m^2*4^n + m*2^n + 1) | none - proven | 173 (7771) 118 (820) 94 (194) 68 (115) 143 (111) 169 (94) 155 (87) 134 (71) 139 (58) 91 (56) | k = 1, 8, 27, 64, and 125 proven composite by full algebraic factors. |
9 | 31, 39, 111, 119 | none - proven | 41 (2446) 94 (57) 76 (26) 74 (25) 61 (22) 83 (13) 52 (11) 103 (10) 56 (10) 114 (9) | ||
10 | 989, 1121, 3653, 3662 | 100, 269, 1343, 2573 (k = 100 at n=2.147G, k = 269 at n=100K, other k at n=3K) | 804 (5470) 3356 (4584) 1024 (4554) 2157 (3560) 2661 (2681) 1844 (1643) 1475 (1128) 2683 (1049) 2311 (1000) 3301 (788) | ||
11 | 5, 7, 17, 19 | none - proven | 10 (10) 16 (8) 13 (2) 12 (2) 9 (2) 4 (2) 1 (2) 18 (1) 15 (1) 14 (1) | ||
12 | 521, 597, 1143, 1509 | 12, 885, 911, 976, 1041, 1433, 1468 (k = 12 at n=33.55M, other k < 1143 at n=25K, k > 1143 at n=3K) | 404 (714558) 1052 (5715) 563 (4020) 1431 (2784) 378 (2388) 846 (1384) 1197 (996) 1247 (751) 1057 (690) 261 (644) | ||
13 | 15, 27, 47, 71 | none - proven (with probable primes that have not been certified: k = 29) | 29 (10574) 48 (6267) 67 (570) 11 (564) 51 (76) 59 (42) 50 (34) 19 (30) 64 (26) 68 (15) | ||
14 | 4, 11, 19, 26 | none - proven | 22 (16) 10 (6) 6 (6) 25 (4) 21 (4) 23 (3) 18 (2) 16 (2) 13 (2) 7 (2) | ||
16 | 38, 194, 524, 608 | All k=4*q^4 for all n: let k=4*q^4 and let m=q*2^n; factors to: (2*m^2 + 2m + 1) * (2*m^2 - 2m + 1) | 89 (25K) | 186 (5229) 459 (3701) 215 (3373) 530 (1210) 23 (1074) 515 (940) 230 (863) 398 (589) 154 (186) 493 (170) | k = 4, 64, and 324 proven composite by full algebraic factors. |
17 | 31, 47, 127, 143 | 53 (3K) | 92 (51311) 88 (4868) 10 (1356) 104 (871) 137 (723) 121 (684) 103 (254) 128 (225) 7 (190) 106 (144) | ||
18 | 398, 512, 571, 989 | 18, 607, 761, 873, 922, 983 (k = 18 at n=16.77M, other k at n=3K) | 122 (292318) 381 (24108) 291 (2415) 37 (457) 523 (440) 987 (409) 547 (317) 457 (262) 362 (258) 123 (236) | ||
19 | 9, 11, 29, 31 | none - proven | 5 (78) 18 (29) 15 (17) 17 (14) 6 (14) 21 (6) 16 (6) 26 (4) 28 (3) 4 (3) | ||
20 | 8, 13, 29, 34 | none - proven | 22 (106) 6 (15) 19 (14) 17 (13) 25 (10) 16 (8) 28 (4) 15 (4) 11 (3) 31 (2) | ||
21 | 23, 43, 47, 111 | none - proven | 67 (2490) 107 (422) 89 (204) 78 (16) 88 (10) 12 (10) 98 (9) 27 (8) 72 (7) 55 (7) | ||
23 | 5, 7, 17, 19 | none - proven | 8 (119215) 10 (3762) 4 (342) 13 (152) 18 (7) 14 (5) 16 (4) 1 (4) 3 (3) 9 (2) | ||
25 | 79, 103, 185, 287 | 71, 181, 222 (k = 71 at n=10K, k = 181 at n=5K, k = 222 at n=350K) | 61 (3104) 89 (815) 40 (518) 209 (376) 80 (304) 119 (198) 223 (187) 283 (186) 194 (117) 151 (112) | ||
26 | 221, 284, 1627, 1766 | 65, 155, 293, 314, 430, 470, 536, 569, 620, 676, 746, 825, 850, 1018, 1025, 1051, 1124, 1152, 1153, 1172, 1229, 1240, 1262, 1270, 1300, 1481, 1531, 1669, 1693, 1750, 1756, 1762 (k = 65 and 155 at n=1M, other k at n=3K) | 607 (1089034) 32 (318071) 640 (66510) 715 (38694) 307 (37834) 217 (11454) 373 (6886) 283 (6882) 998 (2423) 398 (2393) | ||
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 (with probable primes that have not been certified: k = 33) | 33 (7876) 21 (112) 29 (54) 39 (13) 9 (10) 42 (7) 40 (5) 36 (4) 26 (4) 22 (4) | k = 1, 8, and 27 proven composite by full algebraic factors. |
29 | 4, 7, 11, 19 | none - proven | 13 (6) 10 (4) 6 (4) 17 (3) 14 (3) 16 (2) 3 (2) 1 (2) 18 (1) 15 (1) | ||
31 | 239, 293, 521, 1025 | 1, 51, 73, 77, 107, 117, 149, 181, 209, 241, 263, 299, 349, 365, 389, 404, 417, 435, 461, 469, 491, 493, 537, 543, 545, 569, 579, 596, 619, 635, 649, 657, 677, 689, 723, 753, 789, 811, 829, 857, 879, 967 (k = 1 at n=524K, other k < 239 at n=6K, other k at n=3K) | 43 (21053) 189 (5570) 674 (2849) 743 (2575) 665 (2366) 581 (2134) 1019 (2091) 551 (2087) 431 (1981) 933 (1830) | ||
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) | 4, 16 (k = 4 at n=1.717G, k = 16 at n=3.435G) | 47 (1223) 26 (63) 55 (44) 41 (43) 48 (37) 52 (16) 9 (13) 45 (12) 31 (12) 34 (10) | k = 1 and 32 proven composite by full algebraic factors. |
33 | 511, 543, 1599, 1631 | 67, 203, 1207, 1317, 1439, 1531, 1563, 1597 (k = 67 and 203 at n=12K, other k at n=3K) | 766 (610412) 36 (23615) 1188 (23614) 407 (10961) 1580 (9213) 1240 (6953) 154 (6846) 596 (6244) 319 (5043) 288 (4583) | ||
34 | 6, 29, 41, 64 | none - proven | 11 (310) 51 (42) 24 (31) 26 (28) 59 (23) 61 (16) 57 (12) 5 (12) 16 (8) 62 (7) | ||
35 | 5, 7, 17, 19 | none - proven | 4 (42) 9 (4) 16 (2) 13 (2) 10 (2) 1 (2) 18 (1) 15 (1) 14 (1) 12 (1) | ||
37 | 39, 75, 87, 191 | 37, 63, 94, 127, 134, 171 (k = 37 at n=524K, k = 94 at n=1M, other k at n=3K) | 19 (5310) 52 (1628) 139 (1526) 18 (461) 113 (389) 181 (245) 72 (120) 133 (77) 143 (69) 179 (66) | ||
38 | 14, 16, 25, 53 | 1 (16.77M) | 2 (2729) 31 (1528) 51 (143) 34 (62) 9 (21) 52 (16) 37 (16) 24 (10) 4 (10) 46 (8) | ||
39 | 9, 11, 29, 31 | none - proven | 19 (831) 17 (10) 26 (8) 27 (5) 20 (5) 10 (4) 25 (2) 21 (2) 16 (2) 13 (2) | ||
41 | 8, 13, 15, 23 | none - proven | 22 (68) 1 (16) 4 (6) 16 (4) 14 (3) 6 (3) 19 (2) 12 (2) 10 (2) 7 (2) | ||
43 | 21, 23, 65, 67 | 37, 56 (both at n=3K) | 31 (833) 13 (580) 9 (498) 3 (171) 5 (38) 63 (35) 17 (34) 54 (27) 41 (24) 15 (23) | ||
44 | 4, 11, 19, 26 | none - proven | 25 (382) 24 (59) 17 (47) 1 (16) 5 (15) 3 (9) 21 (8) 10 (6) 22 (4) 12 (3) | ||
45 | 47, 91, 231, 275 | 139, 217 (both at n=3K) | 24 (18522) 235 (1832) 114 (1439) 93 (1180) 149 (615) 243 (276) 75 (230) 59 (184) 187 (150) 212 (95) | ||
47 | 5, 7, 8, 16 | none - proven | 2 (175) 13 (40) 1 (8) 11 (5) 12 (3) 10 (2) 9 (2) 4 (2) 15 (1) 14 (1) | ||
49 | 31, 79, 179, 191 | none - proven | 186 (33764) 183 (1610) 96 (662) 141 (522) 43 (176) 24 (165) 121 (126) 101 (108) 167 (102) 94 (91) | ||
50 | 16, 35, 67, 86 | 1 (16.77M) | 37 (956) 33 (683) 7 (516) 59 (135) 42 (80) 79 (72) 44 (53) 31 (28) 69 (22) 58 (14) | ||
51 | 25, 27, 77, 79 | none - proven | 38 (4881) 61 (310) 52 (183) 45 (182) 41 (80) 66 (74) 48 (32) 73 (18) 54 (12) 40 (12) | ||
53 | 7, 11, 31, 35 | 4, 17, 19 (k = 4 at n=2M, other k at n=3K) | 8 (227183) 6 (143) 13 (28) 30 (18) 10 (16) 27 (14) 18 (11) 5 (9) 1 (8) 25 (4) | ||
54 | 21, 34, 76, 89 | none - proven | 74 (311) 19 (103) 81 (102) 36 (86) 16 (30) 66 (20) 61 (16) 60 (16) 53 (15) 67 (12) | ||
55 | 13, 15, 41, 43 | 1, 36 (k = 1 at n=524K, k = 36 at n=1M) | 22 (92) 33 (54) 21 (18) 30 (12) 10 (9) 37 (4) 39 (3) 40 (2) 38 (2) 29 (2) | ||
56 | 20, 37, 77, 94 | 46 (3K) | 39 (394) 35 (243) 85 (100) 4 (78) 19 (70) 34 (34) 26 (27) 68 (21) 30 (19) 76 (18) | ||
57 | 47, 175, 231, 311 | 117, 207 (both at n=3K) | 150 (15759) 14 (14955) 181 (1319) 201 (189) 287 (187) 303 (133) 236 (125) 291 (104) 163 (98) 217 (95) | ||
59 | 4, 5, 7, 9 | none - proven | 8 (5) 2 (3) 6 (2) 1 (2) 3 (1) | ||
61 | 63, 123, 311, 371 | 119, 127, 155, 164, 230, 249, 262, 324, 340, 342, 353, 359, 368 (all at n=3K) | 62 (3698) 43 (2788) 152 (2479) 114 (1706) 23 (1659) 309 (773) 295 (719) 165 (286) 135 (267) 222 (238) | ||
62 | 8, 13, 29, 34 | 1, 27 (k = 1 at n=16.77M, k = 27 at n=3K) | 16 (2580) 7 (308) 22 (248) 32 (139) 14 (67) 10 (66) 2 (43) 25 (40) 12 (27) 33 (22) | ||
64 | 14, 51, 79, 116 | All k = m^3 for all n; factors to: (m*4^n - 1) * (m^2*16^n + m*4^n + 1) | none - proven | 11 (3222) 89 (1269) 94 (97) 98 (42) 86 (36) 24 (31) 91 (28) 101 (22) 84 (21) 92 (14) | k = 1, 8, 27, and 64 proven composite by full algebraic factors. |
81 | 575, 649, 655, 1167 | All k=4*q^4 for all n: let k=4*q^4 and let m=q*3^n; factors to: (2*m^2 + 2m + 1) * (2*m^2 - 2m + 1) | 239, 335, 514, 698, 964, 1007 (k < 575 at n=5K, other k at n=3K) | 558 (51992) 778 (14903) 311 (7834) 621 (5205) 75 (3309) 569 (2937) 439 (2097) 284 (1455) 821 (1378) 831 (1337) | k = 4, 64, 324, and 1024 proven composite by full algebraic factors. |
100 | 62, 233, 332, 836 | 100, 269, 335, 433 (k = 100 at n=1.073G, k = 269 at n=50K, k = 335 at n=3K, k = 433 at n=1M) | 684 (563559) 64 (529397) 75 (16392) 591 (13007) 594 (2932) 804 (2735) 563 (1044) 764 (807) 349 (784) 712 (711) | ||
128 | 44, 85, 98, 173 | 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) | 16, 40, 47, 83, 88, 94, 122 (k = 16 at n=4.908G, other k at n=1.2857M) | 171 (102533) 118 (44110) 41 (39271) 158 (17403) 52 (15608) 42 (13001) 146 (4567) 156 (1083) 136 (1044) 172 (760) | k = 1 proven composite by full algebraic factors. k = 8 and 32 have no possible prime. |
256 | 38, 194, 467, 524 | All k=4*q^4 for all n: let k=4*q^4 and let m=q*4^n; factors to: (2*m^2 + 2m + 1) * (2*m^2 - 2m + 1) | 89, 116, 215, 230, 281, 329, 383, 398, 407, 434, 459, 504 (all at n=3K) | 11 (5702) 346 (2914) 449 (2518) 263 (1914) 523 (1428) 368 (1354) 51 (1198) 309 (1088) 180 (768) 129 (652) | k = 4, 64, and 324 proven composite by full algebraic factors. |
512 | 18, 20, 37, 47 | All k = m^3 for all n; factors to: (m*8^n + 1) * (m^2*64^n - m*8^n + 1) | 2, 4, 5, 16, 32, 34 (k = 2 at n=2.001P, k = 4 at n=62.54T, k = 5 at n=1M, k = 16 at n=1.954T, k = 32 at n=3.817G, k = 34 at n=3K) | 25 (1058) 19 (1050) 42 (44) 31 (24) 44 (23) 12 (23) 14 (21) 7 (20) 11 (9) 46 (8) | k = 1, 8, and 27 proven composite by full algebraic factors. |
1024 | 81, 124, 286, 329 | 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) | 4, 16, 29, 38, 56, 94, 101, 119, 139, 152, 164, 176, 194, 199, 208, 219, 227, 239, 242, 245, 247, 254, 256, 269, 281, 326 (all at n=3K) | 174 (189139) 321 (44248) 171 (29984) 114 (8969) 111 (6130) 96 (4266) 138 (4069) 44 (1933) 187 (1779) 304 (1703) | k = 1, 32, and 243 proven composite by full algebraic factors. |