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 A189906 #7 Jul 22 2025 11:56:14 %S A189906 15,225,3375,35656,372850,3833322,39048081,395408137,3984364191, %T A189906 40031462211,401659633507,4025118368372,40315220042932, %U A189906 403641830599161,4040392891662855,40438586707202572,404700496922543129 %N A189906 Number of 4Xn binary arrays without the pattern 0 0 1 1 diagonally, vertically, antidiagonally or horizontally. %C A189906 Row 4 of A189905 %H A189906 R. H. Hardin, <a href="/A189906/b189906.txt">Table of n, a(n) for n = 1..200</a> %e A189906 Some solutions for 4X4 %e A189906 ..0..0..0..0....0..1..1..0....0..1..0..1....1..1..1..0....1..0..1..1 %e A189906 ..1..1..1..1....0..0..0..1....1..1..0..0....0..1..0..1....1..1..0..0 %e A189906 ..0..0..0..0....1..0..1..0....1..0..0..1....1..0..0..0....0..0..1..0 %e A189906 ..1..0..0..0....0..1..0..0....0..0..1..0....0..1..1..0....0..1..0..1 %K A189906 nonn %O A189906 1,1 %A A189906 _R. H. Hardin_ May 01 2011