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 A226757 #31 Jan 14 2024 11:52:37 %S A226757 1,16,16,16,81,256,256,81,256,1296,1296,256,2401,4096,1296,256,6561, %T A226757 4096,10000,1296,4096,20736,20736,1296,14641,38416,14641,4096,50625, %U A226757 20736,65536,2401,20736,104976,20736,4096,130321,160000,38416,6561,194481,65536 %N A226757 a(n) = number of distinct quadruples of squares modulo n. %F A226757 a(n) = A000224(n)^4. - _Andrew Howroyd_, Aug 06 2018 %Y A226757 Cf. A000224, A068197. %K A226757 nonn,mult %O A226757 1,2 %A A226757 _José María Grau Ribas_, Jun 16 2013 %E A226757 Name corrected by _Andrew Howroyd_, Aug 06 2018