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 A023291 #32 Aug 28 2024 14:45:33 %S A023291 2,1487,2207,2927,8807,11117,16187,17657,26357,44927,45377,48497, %T A023291 91757,110237,117167,122327,125387,126107,145007,170927,174527,190787, %U A023291 193847,203897,230567,244247,246017,270287,280547,283937,347957,362237,364337 %N A023291 Primes that remain prime through 3 iterations of function f(x) = 8x + 1. %C A023291 Primes p such that 8*p+1, 64*p+9 and 512*p+73 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023291 John Cerkan, <a href="/A023291/b023291.txt">Table of n, a(n) for n = 1..10000</a> %F A023291 a(n) == 17 (mod 30) for n > 1. - _John Cerkan_, Sep 23 2016 %t A023291 okQ[n_]:=And@@PrimeQ[NestList[8#+1&,n,3]]; Select[Prime[Range[50000]],okQ] (* _Harvey P. Dale_, Jan 09 2011 *) %o A023291 (Magma) [n: n in [1..450000] | IsPrime(n) and IsPrime(8*n+1) and IsPrime(64*n+9) and IsPrime(512*n+73)]; // _Vincenzo Librandi_, Aug 04 2010 %Y A023291 Subsequence of A005123, A023228, and A023260. %K A023291 nonn %O A023291 1,1 %A A023291 _David W. Wilson_