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 A271021 #6 Apr 05 2016 00:20:10 %S A271021 21609,86436,194481,257049,345744,540225,777924,1028196,1058841, %T A271021 1172889,1382976,1750329,2160900,2313441,2614689,3111696,3651921, %U A271021 4112784,4235364,4691556,4862025,5531904,6245001,6426225,7001316,7800849,8311689,8643600,9253764,9529569 %N A271021 Magic sums of 3 X 3 semimagic squares of squares whose rows, columns, and at least one of the two main diagonals sum to the same number. %H A271021 <a href="/index/Mag#magic">Index entries for sequences related to magic squares</a> %Y A271021 Cf. A267118, A271020, A271022. Subsequence of A269061. Supersequence of A271022. %K A271021 nonn %O A271021 1,1 %A A271021 _Arkadiusz Wesolowski_, Mar 28 2016