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 A229868 #6 Jul 23 2025 05:48:06 %S A229868 5,125,40625,266515625,36821326171875,110831249753697265625 %N A229868 Number of n X n 0..4 arrays with corresponding row and column sums equal. %C A229868 Column 4 of A229870 %e A229868 Some solutions for n=4 %e A229868 ..0..0..0..1....0..0..1..1....0..0..1..0....0..0..1..0....0..0..1..0 %e A229868 ..0..0..2..1....0..0..2..1....0..0..1..2....0..0..2..0....0..0..4..1 %e A229868 ..1..2..4..0....2..2..3..2....1..0..2..4....0..2..2..4....1..4..0..0 %e A229868 ..0..1..1..0....0..1..3..0....0..3..3..4....1..0..3..2....0..1..0..0 %K A229868 nonn %O A229868 1,1 %A A229868 _R. H. Hardin_, Oct 01 2013