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 A319233 #23 Sep 17 2018 03:27:16 %S A319233 0,1,8,28,32,128,2048,8192,23948,131072,524288,8388608,536870912, %T A319233 2147483648,137438953472 %N A319233 Numbers k such that k^2 + 1 divides 2^k + 4. %C A319233 This sequence corresponds to numbers k such that k^2 + 1 divides 2^k + 2^m where m = 2 (A247220 (m = 0), A319216 (m = 1)). %C A319233 a(16) > 10^12. - _Hiroaki Yamanouchi_, Sep 17 2018 %e A319233 32 = 2^5 is a term since (2^(2^5) + 2^2)/((2^5)^2 + 1) = 2^22 - 2^12 + 2^2. %o A319233 (PARI) isok(n)=Mod(2, n^2+1)^n==-4; %Y A319233 Cf. A034785, A247220, A319216. %K A319233 nonn,more %O A319233 1,3 %A A319233 _Altug Alkan_, Sep 14 2018 %E A319233 a(15) from _Hiroaki Yamanouchi_, Sep 17 2018