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 A188868 #7 Jul 22 2025 11:26:14 %S A188868 7,49,316,2032,13045,83737,537496,3450100,22145617,142149013, %T A188868 912430732,5856740200,37593435373,241305971377,1548902653984, %U A188868 9942146967292,63816977822953,409630502531629,2629349654724052,16877355480293296 %N A188868 Number of nX3 binary arrays without the pattern 0 0 0 antidiagonally or horizontally. %C A188868 Column 3 of A188874 %H A188868 R. H. Hardin, <a href="/A188868/b188868.txt">Table of n, a(n) for n = 1..200</a> %F A188868 Empirical: a(n) = 7*a(n-1) -3*a(n-2) -5*a(n-3) +2*a(n-4) %e A188868 Some solutions for 4X3 %e A188868 ..0..1..1....1..0..1....0..1..0....1..1..1....1..0..0....0..1..1....0..0..1 %e A188868 ..1..0..1....0..1..0....1..1..0....1..0..1....1..1..0....1..1..1....0..1..0 %e A188868 ..1..1..0....0..1..1....0..1..1....1..0..0....0..1..0....1..1..1....0..1..1 %e A188868 ..1..1..0....0..1..1....1..1..0....1..1..1....1..0..0....0..0..1....1..0..0 %K A188868 nonn %O A188868 1,1 %A A188868 _R. H. Hardin_ Apr 12 2011