This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A122095 #24 Jul 22 2024 23:31:26 %S A122095 11,29,179,239,431,761,857,941,1367,1667,1871,1877,2411,2837,3041, %T A122095 3119,3329,3347,3767,4289,5021,5087,5231,5261,5717,5861,6449,6917, %U A122095 6959,7079,7211,7919,8429,8741,8867,9341,9461,9851,10211,10979,12107,12437,12479 %N A122095 Primes p for which 8*p+1 divides 2^p-1. %C A122095 The first 962 terms, all those with n<500000, are also in A023228. - _R. J. Mathar_, Oct 20 2006 %C A122095 All terms are in A023228, i.e., such that 8p+1 is prime, since a divisor of 8p+1 would also divide M(p)=A000225(p) and thus be of the form 2kp+1, but it is easily checked that 8p+1 cannot be a multiple of 2p+1 (nor of 4p+1 or 6p+1, of course). - _M. F. Hasler_, Mar 21 2011 %H A122095 Amiram Eldar, <a href="/A122095/b122095.txt">Table of n, a(n) for n = 1..10000</a> %e A122095 29 is in this sequence because 2^29-1 is divisible by 8 * 29 + 1 = 233. %p A122095 isA122095 := proc(n) RETURN( isprime(n) and ( (2^n-1) mod (8*n+1)) = 0 ) ; end: n := 1 : for a from 2 to 500000 do if isA122095(a) then print(n,a) ; n := n+1 ; fi ; od ; # _R. J. Mathar_, Oct 20 2006 %t A122095 Select[Prime[Range[1500]],Divisible[2^#-1,8#+1]&] (* _Harvey P. Dale_, Dec 18 2012 *) %t A122095 Select[Prime[Range[1500]],PowerMod[2,#,8#+1]==1&] (* _Harvey P. Dale_, May 28 2015 *) %o A122095 (PARI) forprime( p=1,1e4, Mod(2,p*8+1)^p-1 || print1(p, ", ")) %Y A122095 Cf. A000225, A002515, A188130. %K A122095 nonn %O A122095 1,1 %A A122095 _J. Lowell_, Oct 17 2006 %E A122095 More terms from _R. J. Mathar_, Oct 20 2006