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 A214008 #6 Jun 02 2025 08:04:55 %S A214008 5,375,564041,17609835599,11798463876314995 %N A214008 Number of n X n nonnegative integer matrices with row and column i=1..n having sum <= i*4. %C A214008 Column 4 of A214011 %e A214008 Some solutions for n=3 %e A214008 ..2..2..0....0..0..0....0..0..0....0..0..3....3..0..1....0..0..0....2..0..0 %e A214008 ..0..6..2....0..2..0....4..1..0....0..0..4....0..5..0....0..8..0....0..4..3 %e A214008 ..0..0..7....0..2..9....0..0..4....0..0..5....0..2..0....0..0..2....0..2..6 %K A214008 nonn %O A214008 1,1 %A A214008 _R. H. Hardin_ Jun 30 2012