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 A269189 #4 Feb 20 2016 09:42:12 %S A269189 60,708,9284,115452,1399612,16629436,194596516,2249848972,25758552060, %T A269189 292530733516,3299601105860,37002081127036,412867979588732, %U A269189 4586651556698652,50758470773069860,559808285415404076 %N A269189 Number of nX3 0..3 arrays with some element plus some horizontally, diagonally, antidiagonally or vertically adjacent neighbor totalling three no more than once. %C A269189 Column 3 of A269194. %H A269189 R. H. Hardin, <a href="/A269189/b269189.txt">Table of n, a(n) for n = 1..210</a> %F A269189 Empirical: a(n) = 22*a(n-1) -131*a(n-2) +88*a(n-3) +221*a(n-4) -154*a(n-5) -101*a(n-6) +44*a(n-7) -4*a(n-8) for n>9 %e A269189 Some solutions for n=4 %e A269189 ..0..0..1. .0..2..3. .1..0..0. .1..1..3. .1..1..3. .3..1..1. .0..0..1 %e A269189 ..1..0..2. .2..2..2. .1..1..1. .3..3..3. .1..1..3. .3..1..0. .0..1..1 %e A269189 ..0..0..2. .2..2..3. .0..1..3. .3..3..3. .3..3..3. .3..1..0. .1..1..1 %e A269189 ..0..2..2. .0..0..2. .1..3..1. .1..1..2. .2..1..1. .3..1..1. .1..1..3 %Y A269189 Cf. A269194. %K A269189 nonn %O A269189 1,1 %A A269189 _R. H. Hardin_, Feb 20 2016