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 A269150 #4 Feb 20 2016 07:18:05 %S A269150 1620,330192,46576336,6004186984,738478504448,88082672552208, %T A269150 10275566914040000,1178661175005532168,133416857282270562320, %U A269150 14941436920498380518848,1658672032118594665963168 %N A269150 Number of nX6 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three exactly once. %C A269150 Column 6 of A269152. %H A269150 R. H. Hardin, <a href="/A269150/b269150.txt">Table of n, a(n) for n = 1..210</a> %e A269150 Some solutions for n=2 %e A269150 ..2..3..3..2..3..2. .3..2..0..1..3..3. .1..1..3..3..2..0. .2..2..3..2..2..0 %e A269150 ..0..1..3..2..2..0. .0..2..0..1..1..1. .0..1..1..1..0..1. .0..2..2..2..2..3 %Y A269150 Cf. A269152. %K A269150 nonn %O A269150 1,1 %A A269150 _R. H. Hardin_, Feb 20 2016