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#1 |
"99(4^34019)99 palind"
Nov 2016
(P^81993)SZ base 36
25×5×23 Posts |
The generalized repunits (b^p-1)/(b-1) with a given factorization status
A = Semiprime and divisible by 2*p+1 B = Semiprime and the two prime factors are both large ((number of digits of the larger prime) / (number of digits of the smaller prime) < 1.3) C = The largest two prime factors are very close ((the larger prime) / (the smaller prime) < 100) Code:
Base A B C 2 11, 23, 83, 131, 3359 67 (a little > 1.3), 101, 137, 149, 523, 727, 1061, 1277? 277 (a little > 100), 397 (all of the largest three prime factors) -2 29, 41, 53, 3329 619 499 3 11, 23, 131 349, 661 (a little > 1.3) 569 -3 (not exist since no 2*p+1 divides (3^p+1)/4) 6 11 67, 353 347 -6 89, 173 23 (none known) 10 (none known) 17 (a little > 1.3), 71, 211 193, 223 -10 29 (none known) (none known) 12 131 311? 23, 193, 239 -12 (not exist since no 2*p+1 divides (12^p+1)/13) Last fiddled with by sweety439 on 2022-02-13 at 22:42 |
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#2 |
"99(4^34019)99 palind"
Nov 2016
(P^81993)SZ base 36
E6016 Posts |
2,727- 122/98 = 1.244897959183...
2,1061- 177/143 = 1.237762237762... 6,353- 155/120 = 1.291666666666... 10,211- 118/93 = 1.268817204301... All them are in the range (1.2,1.3), the "most beautiful" range and 2,523- 90/69 = 1.304347826086... ("a little" larger than 1.3) However, base 3 and 12 have no known prime in this range: 3,349- 87/80 = 1.0875 (too small) 3,373- 106/73 = 1.452054794520... (too large) 3,661- 182/134 = 1.358208955223... (too large) ---------------------------------------------------------------------------------------------------------------- 3,569- P115*P116 6,347- P96*P96 10,193- P54*P55 10,223- P105*P107 10,337- P101*P102 (recently found!!!) 12,193- P77*P77 12,239- P101*P102 However, base 2 has no known example with large two prime factors are P(n)*P(n) or P(n)*P(n+1) or P(n)*P(n+2) ---------------------------------------------------------------------------------------------------------------- (2^p-1)/(2*p+1) is prime for p = 11, 23, 83, 131, 3359 (3^p-1)/2/(2*p+1) is prime for p = 11, 23, 131 (6^p-1)/5/(2*p+1) is prime for p = 11 (12^p-1)/11/(2*p+1) is prime for p = 131 However, base 10 has no known such example, i.e. there is no known prime p such that (10^p-1)/9/(2*p+1) is prime Last fiddled with by sweety439 on 2023-01-01 at 10:41 |
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