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 A202554 #7 Jul 22 2025 16:38:47 %S A202554 3,8,17,37,73,151,293,598,1159,2358,4581,9314,18143,36880,72001, %T A202554 146325,286185,581427,1138813,2312865,4535493,9207989,18074789, %U A202554 36682275,72066977,146206411,287454709,582979035,1146938817,2325328271,4577459549 %N A202554 Number of nX2 0,1 arrays with the row and column sums nondecreasing. %C A202554 Column 2 of A202560 %H A202554 R. H. Hardin, <a href="/A202554/b202554.txt">Table of n, a(n) for n = 1..210</a> %e A202554 Some solutions for n=10 %e A202554 ..0..1....1..0....0..0....0..0....0..0....0..1....0..1....0..0....0..0....0..0 %e A202554 ..0..1....0..1....0..0....0..1....0..0....1..0....0..1....0..0....0..1....0..1 %e A202554 ..0..1....1..0....0..0....0..1....0..0....1..0....1..0....0..1....1..0....1..0 %e A202554 ..0..1....0..1....0..1....1..0....0..1....0..1....0..1....0..1....0..1....0..1 %e A202554 ..0..1....1..0....0..1....1..0....0..1....1..0....0..1....0..1....1..0....0..1 %e A202554 ..0..1....0..1....0..1....1..0....0..1....0..1....0..1....1..0....0..1....1..0 %e A202554 ..1..0....0..1....1..0....1..0....0..1....0..1....0..1....1..1....0..1....0..1 %e A202554 ..1..0....1..0....1..0....0..1....0..1....0..1....0..1....1..1....1..1....1..0 %e A202554 ..1..0....0..1....0..1....0..1....0..1....0..1....1..0....1..1....1..1....0..1 %e A202554 ..1..0....1..0....1..1....0..1....1..1....1..1....1..1....1..1....1..1....0..1 %K A202554 nonn %O A202554 1,1 %A A202554 _R. H. Hardin_ Dec 21 2011