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 A189900 #7 Jul 22 2025 11:55:38 %S A189900 15,225,3375,35656,377517,3810503,36890502,354894796,3368920072, %T A189900 31765314572,298643477857,2799075682549,26196661596588, %U A189900 244952250115880,2288817676141909,21378736239048787,199638668209430098 %N A189900 Number of nX4 binary arrays without the pattern 0 0 1 1 diagonally, vertically, antidiagonally or horizontally. %C A189900 Column 4 of A189905 %H A189900 R. H. Hardin, <a href="/A189900/b189900.txt">Table of n, a(n) for n = 1..200</a> %e A189900 Some solutions for 5X4 %e A189900 ..0..0..0..0....0..1..0..0....0..0..0..1....0..0..0..1....0..1..0..0 %e A189900 ..0..0..0..0....1..0..1..1....1..1..1..1....0..0..0..0....1..1..1..0 %e A189900 ..0..0..0..0....0..1..0..0....1..1..0..1....0..0..0..1....0..1..1..0 %e A189900 ..1..1..0..0....0..1..0..1....1..1..0..1....0..0..0..1....0..0..1..0 %e A189900 ..0..0..0..0....1..1..0..1....0..1..0..1....1..1..0..1....1..0..1..0 %K A189900 nonn %O A189900 1,1 %A A189900 _R. H. Hardin_ May 01 2011