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 A202556 #7 Jul 22 2025 16:39:02 %S A202556 5,37,235,1526,9325,57255,342295,2048759,12097875,71623580,421070137, %T A202556 2483305077,14588495861,85996521989,505767515227,2984447588198, %U A202556 17583885515973,103920730449567,613473612747653,3631554358770128 %N A202556 Number of nX4 0,1 arrays with the row and column sums nondecreasing. %C A202556 Column 4 of A202560 %H A202556 R. H. Hardin, <a href="/A202556/b202556.txt">Table of n, a(n) for n = 1..46</a> %e A202556 Some solutions for n=6 %e A202556 ..1..0..1..0....0..0..0..0....0..0..1..0....0..0..0..0....0..1..0..0 %e A202556 ..0..1..0..1....0..0..0..0....1..0..0..1....0..1..0..1....1..0..0..0 %e A202556 ..0..1..0..1....0..0..0..0....0..1..0..1....1..0..0..1....0..0..0..1 %e A202556 ..0..0..1..1....1..0..0..1....0..1..0..1....0..1..1..0....0..0..0..1 %e A202556 ..1..1..0..0....0..0..1..1....1..0..1..1....0..0..1..1....0..0..1..0 %e A202556 ..0..0..1..1....0..1..1..1....0..1..1..1....1..1..1..1....0..0..0..1 %K A202556 nonn %O A202556 1,1 %A A202556 _R. H. Hardin_ Dec 21 2011