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 A213218 #6 Mar 02 2013 15:25:09 %S A213218 20,192,352,104,736,264,64,464,1088,640,1344,800,3136,896,1952,2496, %T A213218 22272,2752,1728,1504,8576,4480,3520,12672,7552,4160,3840,11520,2304, %U A213218 19712,9088,8000,10880,14592,11904,4864,21248,8448,17664,26624,10112,6528,5696,6208,24704,22912,28480,9536,39168,41216,36736 %N A213218 Even numbers in A221715. %Y A213218 Cf. A114183, A221715. %K A213218 nonn %O A213218 1,1 %A A213218 _N. J. A. Sloane_, Mar 02 2013