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 A224256 #8 Mar 18 2025 22:33:19 %S A224256 3,36,648,12467,238366,4480391,83124099,1530419762,28072690614, %T A224256 514262753781,9420094252771 %N A224256 Number of n X n 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing. %e A224256 Some solutions for n=3: %e A224256 ..0..2..0....0..1..0....0..0..0....1..1..0....1..2..0....2..1..1....0..1..0 %e A224256 ..0..2..0....0..1..0....2..0..0....2..2..1....2..2..0....2..2..2....2..2..2 %e A224256 ..0..2..0....1..1..2....2..1..0....2..2..2....2..2..0....2..2..2....2..2..2 %Y A224256 Main diagonal of A224262. %K A224256 nonn,more %O A224256 1,1 %A A224256 _R. H. Hardin_, Apr 02 2013 %E A224256 Name corrected by _Andrew Howroyd_, Mar 18 2025