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 A133323 #6 Feb 16 2025 08:33:06 %S A133323 7,19,37,61,127,169,271,331,397,547,631,919,1657,1801,1951,2269,2437, %T A133323 2791,3169,3571,4219,4447,5167,5419,6211,7057,7351,8269,9241,10267, %U A133323 11719,12097,13267,13669,16651,19441,19927,22447,23497,24571,25117,26227,27361 %N A133323 Hex (or centered hexagonal) numbers that are prime powers of the form (6n+1)^k. %C A133323 Intersection of A003215 and A133290. %H A133323 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HexNumber.html">Hex Number</a>. %Y A133323 Cf. A004611. %K A133323 nonn %O A133323 1,1 %A A133323 _Mats Granvik_, Oct 18 2007, Oct 19 2007