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 A229368 #6 Jul 23 2025 05:41:01 %S A229368 60,869,13937,222990,3576912,56939585,911301584,14532090528, %T A229368 232232172607,3706745079815,59203178820148,945256319974208, %U A229368 15094878048962231,241030410158025724,3848864771555252792,61458856647843842612 %N A229368 Number of nX4 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 antidiagonally. %C A229368 Column 4 of A229372 %H A229368 R. H. Hardin, <a href="/A229368/b229368.txt">Table of n, a(n) for n = 1..210</a> %F A229368 Empirical: a(n) = 2*a(n-1) +257*a(n-2) +433*a(n-3) -16073*a(n-4) -20963*a(n-5) +481391*a(n-6) +119200*a(n-7) -7182420*a(n-8) +4731824*a(n-9) +44618241*a(n-10) -29900281*a(n-11) -162825007*a(n-12) +45010518*a(n-13) +361117327*a(n-14) +96538808*a(n-15) -378171592*a(n-16) -303446432*a(n-17) +22354064*a(n-18) +83608448*a(n-19) +6923904*a(n-20) -10505152*a(n-21) -433920*a(n-22) +664576*a(n-23) -65536*a(n-24) for n>25 %e A229368 Some solutions for n=3 %e A229368 ..1..0..1..2....0..2..1..2....1..2..0..2....0..1..0..1....1..2..1..2 %e A229368 ..1..0..0..1....0..1..0..1....0..1..2..0....0..1..2..2....2..0..1..0 %e A229368 ..2..2..2..1....0..2..1..2....0..2..1..2....2..2..1..0....1..0..2..2 %K A229368 nonn %O A229368 1,1 %A A229368 _R. H. Hardin_ Sep 21 2013