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 A137193 #2 Mar 30 2012 18:49:09 %S A137193 0,0,1,2,10,46,215,1037,5083,24918,122437 %N A137193 Number of n-celled polyhexes with perimeter < 4n+2. %C A137193 These are n-cell polyhexes with the perimeter less than the maximum possible one. %C A137193 If we associate a graph to a polyhex with vertices representing cells and edges representing two cells with a common edge, then this sequence enumerates polyhexes whose corresponding graphs have cycles. %F A137193 A000228(n)-A038142(n) %K A137193 hard,more,nonn %O A137193 1,4 %A A137193 _Tanya Khovanova_, Mar 03 2008