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 A234952 #5 Jan 15 2014 13:53:48
%S A234952 4,60,120,2320,1552848,10080,139714902540,93294624780,228657996794220,
%T A234952 4756736241732916394976,20024071474861042488900,
%U A234952 2176937111336664570375832140,15366743578393906356665002406454800354974137359272445859047945613961394951904884493965220
%N A234952 Apply the map k -> L(k)/gcd(L(k),k-1) to the sequence A007850 of Giuga numbers, where L(k) is the Carmichael lambda function A002322.
%H A234952 J. M. Grau and A. M. Oller-Marcén, <a href="http://arxiv.org/abs/1311.3522">On the congruence sum_{j=1}^{n-1} j^{k(n-1)} == -1 (mod n); k-strong Giuga and k-Carmichael numbers</a>, arXiv preprint arXiv:1311.3522, 2013
%Y A234952 Cf. A007850, A002322.
%K A234952 nonn
%O A234952 1,1
%A A234952 _N. J. A. Sloane_, Jan 12 2014