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 A250652 #7 Jul 23 2025 12:39:21 %S A250652 9,34,109,316,859,2234,5625,13816,33271,78838,184309,425972,974835, %T A250652 2211826,4980721,11141104,24772591,54788078,120586221,264241132, %U A250652 576716779,1254096874,2717908969,5872025576,12650020839,27179089894 %N A250652 Number of (n+1)X(n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. %C A250652 Diagonal of A250656 %H A250652 R. H. Hardin, <a href="/A250652/b250652.txt">Table of n, a(n) for n = 1..69</a> %e A250652 Some solutions for n=4 %e A250652 ..0..0..0..0..0....1..1..0..0..0....1..1..1..1..0....1..0..0..0..0 %e A250652 ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %e A250652 ..0..0..0..0..0....0..1..1..1..1....0..0..0..0..0....1..1..1..1..1 %e A250652 ..0..0..0..0..0....0..1..1..1..1....0..0..0..0..0....0..0..1..1..1 %e A250652 ..0..0..1..1..1....0..1..1..1..1....0..1..1..1..1....0..0..1..1..1 %K A250652 nonn %O A250652 1,1 %A A250652 _R. H. Hardin_, Nov 26 2014