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 A202648 #8 Jul 22 2025 16:45:17 %S A202648 2,8,126,10016,3648810,5616280768,35610018145138 %N A202648 Number of n X n 0..1 arrays with no row or column sum equal to the previous. %C A202648 Column 1 of A202651 %e A202648 Some solutions for n=3 %e A202648 ..1..0..1....0..0..0....1..1..0....0..1..0....0..0..1....0..1..0....0..1..1 %e A202648 ..0..0..0....1..0..1....0..1..0....0..1..1....0..1..1....0..1..1....0..1..0 %e A202648 ..1..0..1....1..0..0....0..0..0....0..1..0....0..0..1....1..1..1....1..1..0 %K A202648 nonn %O A202648 1,1 %A A202648 _R. H. Hardin_ Dec 22 2011