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 A297414 #14 Sep 06 2021 10:20:52 %S A297414 1,4,9,12,25,36,40,52,80,92,124,150,208,306,361,630,656,1648,1780, %T A297414 2508,3300,3540,5728,6260,6450,7500,10820,12656,14076,14132,18836, %U A297414 20960,23456,24272,35280,43136 %N A297414 Numbers k such that 2^m == 2 (mod m*(m+1)), where m = A019320(k). %C A297414 Also, numbers k such that A019320(k) belongs to A216822. %o A297414 (PARI) is_A297414(k) = my(m=polcyclo(k, 2)); Mod(2, m*(m+1))^m==2; %Y A297414 Cf. A019320, A216822, A297413, A297415. %K A297414 nonn %O A297414 1,2 %A A297414 _Max Alekseyev_, Dec 29 2017