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 A250537 #6 Jul 23 2025 12:31:10 %S A250537 150,10704,644779,27240292,824599694,19031828420,355022719767, %T A250537 5607306662836 %N A250537 Number of (n+1)X(n+1) 0..3 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 A250537 Diagonal of A250544 %e A250537 Some solutions for n=2 %e A250537 ..2..1..0....1..1..1....2..2..3....3..1..2....3..1..1....3..1..0....3..3..1 %e A250537 ..0..3..2....2..2..3....0..0..1....2..0..1....1..1..1....1..1..2....1..3..1 %e A250537 ..0..3..3....0..2..3....1..1..3....0..0..1....0..1..3....0..1..3....0..3..1 %K A250537 nonn %O A250537 1,1 %A A250537 _R. H. Hardin_, Nov 24 2014