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 A180761 #5 Jul 22 2025 08:29:13 %S A180761 0,3,63,4475,1154119,1064583557,3538520414645,42325704140613463, %T A180761 1822180205677117048273,282344956970612464702333909, %U A180761 157459613671260527898784781898227 %N A180761 Half the number of n X n binary arrays with each element equal to at least one neighbor. %C A180761 Diagonal of A180771 %K A180761 nonn %O A180761 1,2 %A A180761 _R. H. Hardin_ Sep 20 2010