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 A207763 #7 Jul 22 2025 20:48:48 %S A207763 6,36,82,221,493,1095,2654,6203,14182,33242,77781,180207,419683, %T A207763 979186,2277663,5301348,12351370,28755901,66942929,155895195, %U A207763 362997882,845159395,1967953186,4582333234,10669471213,24843252803,57846384111 %N A207763 Number of 3Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically. %C A207763 Row 3 of A207762 %H A207763 R. H. Hardin, <a href="/A207763/b207763.txt">Table of n, a(n) for n = 1..210</a> %F A207763 Empirical: a(n) = a(n-1) +8*a(n-3) +a(n-5) -12*a(n-6) -3*a(n-7) +a(n-8) +10*a(n-9) -2*a(n-10) -3*a(n-12) for n>14 %e A207763 Some solutions for n=4 %e A207763 ..1..1..1..0....0..1..1..1....0..1..0..0....1..1..0..0....1..1..1..0 %e A207763 ..0..0..1..0....0..1..0..0....1..1..0..0....1..0..0..1....0..0..1..1 %e A207763 ..0..0..1..1....0..1..0..0....0..1..1..1....0..0..1..0....0..0..1..0 %K A207763 nonn %O A207763 1,1 %A A207763 _R. H. Hardin_ Feb 19 2012