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 A188741 #7 Jul 22 2025 11:19:56 %S A188741 8,64,292,1651,9504,52072,289776,1617326,8992115,50039730,278556885, %T A188741 1550225927,8627663414,48018101493,267244802833,1487352476813, %U A188741 8277889631533,46070713404315,256407195751421,1427038070447781 %N A188741 Number of nX3 binary arrays without the pattern 1 1 1 diagonally, vertically or antidiagonally. %C A188741 Column 3 of A188747 %H A188741 R. H. Hardin, <a href="/A188741/b188741.txt">Table of n, a(n) for n = 1..200</a> %F A188741 Empirical: a(n) = 2*a(n-1) +9*a(n-2) +50*a(n-3) +55*a(n-4) +37*a(n-5) -108*a(n-6) -111*a(n-7) +89*a(n-8) +27*a(n-9) -28*a(n-10) -5*a(n-11) -48*a(n-12) -28*a(n-13) -17*a(n-14) -4*a(n-15) -a(n-16) %e A188741 Some solutions for 4X3 %e A188741 ..0..0..0....0..0..1....1..0..0....0..0..0....0..1..0....0..0..0....0..1..1 %e A188741 ..0..1..1....1..0..1....0..0..0....0..0..0....0..0..1....0..1..0....0..0..1 %e A188741 ..1..0..0....0..0..0....0..0..1....0..0..1....1..1..0....1..0..0....1..1..0 %e A188741 ..0..0..0....1..1..1....1..0..1....0..1..1....0..1..1....0..0..1....0..1..0 %K A188741 nonn %O A188741 1,1 %A A188741 _R. H. Hardin_ Apr 09 2011