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 A230064 #6 Jun 02 2025 08:40:43 %S A230064 0,81,441,15129,281961,6487209,137945025,3020271849,65409597009, %T A230064 1422349620129,30882371810481,670905678011409,14572037106084249, %U A230064 316528933014939681,6875333045808325641,149340930039835655625 %N A230064 Number of nX4 0..2 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j). %C A230064 Column 4 of A230068 %H A230064 R. H. Hardin, <a href="/A230064/b230064.txt">Table of n, a(n) for n = 1..210</a> %F A230064 Empirical: a(n) = 17*a(n-1) +132*a(n-2) -633*a(n-3) -223*a(n-4) +1688*a(n-5) +49*a(n-6) -593*a(n-7) +68*a(n-8) +9*a(n-9) -a(n-10) for n>11 %e A230064 Some solutions for n=4 %e A230064 ..1..1..0..1....1..1..0..0....2..2..2..0....1..1..1..1....1..2..1..1 %e A230064 ..1..1..1..2....1..1..2..2....0..0..2..1....1..1..1..1....0..1..1..0 %e A230064 ..1..1..1..1....2..2..2..1....1..0..1..1....0..2..2..0....2..0..2..1 %e A230064 ..1..1..1..1....0..0..1..0....2..1..1..1....0..2..2..0....2..0..1..0 %K A230064 nonn %O A230064 1,2 %A A230064 _R. H. Hardin_, Oct 08 2013