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 A319370 #14 Sep 21 2018 11:06:13 %S A319370 91,18227,28605,137481,538849,2832797,3220333,384792005 %N A319370 Composite numbers k such that phi(k)^phi(k) == k + 1 (mod k^2). %C A319370 Composite numbers k such that (k-phi(k))^phi(k) == 1 (mod k^2). %o A319370 (PARI) isok(n) = n>1 && !isprime(n) && Mod(n-eulerphi(n), n^2)^eulerphi(n)==1; %Y A319370 Cf. A003277, A077816. %K A319370 nonn,more %O A319370 1,1 %A A319370 _Altug Alkan_, Sep 17 2018