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 A180769 #5 Jul 22 2025 08:30:00 %S A180769 21,12377,3365327,953982820,273289411333,78060898850787, %T A180769 22310318523546774,6375989200126477033,1822180205677117048273, %U A180769 520757452730725828979262,148826239836327503673819877 %N A180769 Half the number of nX9 binary arrays with each element equal to at least one neighbor. %C A180769 Column 9 of A180771 %H A180769 R. H. Hardin, <a href="/A180769/b180769.txt">Table of n, a(n) for n=1..99</a> %K A180769 nonn %O A180769 1,1 %A A180769 _R. H. Hardin_ Sep 20 2010