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 A223638 #7 Jul 23 2025 04:19:27 %S A223638 2,16,218,2962,36947,428187,4682514,49045356,497721760,4944054774 %N A223638 Number of n X n 0..1 arrays with rows, columns, diagonals and antidiagonals unimodal. %C A223638 Diagonal of A223644 %e A223638 Some solutions for n=4 %e A223638 ..0..0..0..1....0..0..1..0....1..1..1..0....0..0..0..0....0..0..0..1 %e A223638 ..0..0..1..1....1..1..0..0....0..1..1..0....1..0..0..0....1..1..1..0 %e A223638 ..0..1..1..1....0..1..0..0....0..0..1..0....0..0..0..1....0..0..0..0 %e A223638 ..0..1..1..0....0..1..0..0....0..0..0..1....0..1..0..0....0..0..0..0 %K A223638 nonn %O A223638 1,1 %A A223638 _R. H. Hardin_ Mar 24 2013