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 A229375 #6 Jul 23 2025 05:41:36 %S A229375 22,126,956,6730,48490,346598,2486980,17808604,127696504,914844004, %T A229375 6558227280,46993954326,336844120550,2413933454878,17301596035866, %U A229375 123994418056868,888689321106698,6369062557713410,45647482408072212 %N A229375 Number of nX3 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 diagonally or antidiagonally. %C A229375 Column 3 of A229380 %H A229375 R. H. Hardin, <a href="/A229375/b229375.txt">Table of n, a(n) for n = 1..210</a> %F A229375 Empirical: a(n) = 4*a(n-1) +50*a(n-2) -133*a(n-3) -653*a(n-4) +1214*a(n-5) +2281*a(n-6) -3420*a(n-7) -2248*a(n-8) +2704*a(n-9) +835*a(n-10) -481*a(n-11) -120*a(n-12) %e A229375 Some solutions for n=4 %e A229375 ..2..0..1....0..0..1....2..2..2....2..1..2....0..1..0....1..2..2....0..1..2 %e A229375 ..1..0..2....1..2..1....0..0..1....1..2..0....1..2..1....0..0..1....1..2..0 %e A229375 ..1..2..1....0..1..0....1..2..1....0..1..0....1..0..0....1..2..2....2..1..0 %e A229375 ..0..1..0....0..2..0....1..0..2....2..2..1....2..1..2....0..0..0....0..1..2 %K A229375 nonn %O A229375 1,1 %A A229375 _R. H. Hardin_ Sep 21 2013