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 A250748 #7 Jul 23 2025 12:45:14 %S A250748 32,237,1353,6663,29814,124785,497471,1911819,7141428,26081157, %T A250748 93524517,330341391,1152105314,3974940633,13587035451,46067386899, %U A250748 155081690112,518770438893,1725559820033,5710472045463,18811007467662,61706609086017 %N A250748 Number of (n+1)X(n+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction. %C A250748 Diagonal of A250755 %H A250748 R. H. Hardin, <a href="/A250748/b250748.txt">Table of n, a(n) for n = 1..53</a> %e A250748 Some solutions for n=4 %e A250748 ..0..0..0..0..0....2..2..2..2..2....1..1..0..0..0....2..2..2..2..2 %e A250748 ..0..0..0..0..0....2..2..2..2..2....0..0..1..1..1....0..0..0..0..0 %e A250748 ..1..1..2..2..2....2..2..2..2..2....0..0..1..1..1....0..0..1..1..1 %e A250748 ..0..0..2..2..2....1..1..1..1..1....0..0..1..1..1....0..0..2..2..2 %e A250748 ..0..0..2..2..2....0..0..2..2..2....1..1..2..2..2....0..0..2..2..2 %K A250748 nonn %O A250748 1,1 %A A250748 _R. H. Hardin_, Nov 27 2014