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 A223631 #7 Jul 23 2025 04:18:55 %S A223631 2,16,229,3712,61545,1026377,17224974,291563806,4984273228, %T A223631 86086143903,1502219415538 %N A223631 Number of n X n 0..1 arrays with rows, antidiagonals and columns unimodal. %C A223631 Diagonal of A223637 %e A223631 Some solutions for n=4 %e A223631 ..1..0..0..0....0..1..0..0....0..0..0..0....0..0..1..0....1..1..1..0 %e A223631 ..1..1..1..1....0..0..0..0....1..1..0..0....1..1..1..1....1..1..1..1 %e A223631 ..1..1..1..1....0..0..0..1....1..1..1..1....0..0..1..1....1..1..1..1 %e A223631 ..0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1....1..1..1..0 %K A223631 nonn %O A223631 1,1 %A A223631 _R. H. Hardin_ Mar 24 2013