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 A269282 #4 Feb 21 2016 09:02:36 %S A269282 0,27634932,23230366488,16128206816904,10181956012212600, %T A269282 6090616046325570480,3516906597130333936872,1980763969657041721006344, %U A269282 1095070756128723603201412440,596778595867621855341816843744 %N A269282 Number of 7Xn 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once. %C A269282 Row 7 of A269276. %H A269282 R. H. Hardin, <a href="/A269282/b269282.txt">Table of n, a(n) for n = 1..210</a> %e A269282 Some solutions for n=2 %e A269282 ..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0 %e A269282 ..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0 %e A269282 ..0..1. .0..3. .0..1. .2..0. .0..2. .0..2. .2..1. .0..1. .2..2. .2..0 %e A269282 ..3..3. .1..0. .1..0. .3..2. .3..1. .3..0. .1..1. .3..1. .2..3. .1..0 %e A269282 ..0..1. .1..1. .1..0. .0..0. .0..1. .1..1. .1..0. .3..0. .2..3. .3..2 %e A269282 ..1..0. .3..1. .2..1. .0..1. .2..0. .1..0. .1..3. .2..2. .3..0. .2..0 %e A269282 ..1..3. .1..0. .3..1. .0..0. .0..1. .2..3. .1..3. .3..2. .2..2. .1..3 %Y A269282 Cf. A269276. %K A269282 nonn %O A269282 1,2 %A A269282 _R. H. Hardin_, Feb 21 2016