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 A269200 #6 Jul 07 2025 20:23:38 %S A269200 8748,3212820,1184381844,399104835612,128136007344516, %T A269200 39825831571425924,12093315071771856492,3608384928930423012804, %U A269200 1062048602869077147571956,309185374985245150329134076,89206481105125372533736647588 %N A269200 Number of n X 7 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three no more than once. %C A269200 Column 7 of A269201. %H A269200 R. H. Hardin, <a href="/A269200/b269200.txt">Table of n, a(n) for n = 1..210</a> %e A269200 Some solutions for n=1 %e A269200 ..1..3..0..0..0..1..1. .2..1..3..1..3..2..3. .1..2..0..0..0..0..2 %Y A269200 Cf. A269201. %K A269200 nonn %O A269200 1,1 %A A269200 _R. H. Hardin_, Feb 20 2016