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 A179003 #14 Jun 28 2024 03:25:38 %S A179003 1,2,4,6,7,10,16,18,19,25,28,30,31,34,36,37,38,43,46,49,52,55,58,61, %T A179003 64,67,70,78,79,87,88,91,96,97,100,106,107,109,112,115,118,124,126, %U A179003 133,138,145,147,148,151,154,156,157,160,163,169,180 %N A179003 Numbers k such that 2^(2*k-1) mod (2*k+1) is prime. %t A179003 fQ[n_] := PrimeQ@ PowerMod[2, 2 n - 1, 2 n + 1]; Select[ Range@ 180, fQ] %Y A179003 Cf. A000040, A178537, A178970. %K A179003 nonn %O A179003 1,2 %A A179003 _Juri-Stepan Gerasimov_, Jan 03 2011