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 A213960 #6 Sep 08 2022 12:57:27 %S A213960 7,980,3323712,256652587891,447939229940051654, %T A213960 17583943206407091985366455 %N A213960 Number of n X n 0..6 matrices with row and column i=1..n having sum <= i*6. %C A213960 Column 6 of A213962. %e A213960 Some solutions for n=4 %e A213960 ..0..2..3..0....1..2..0..0....2..3..0..0....1..1..3..0....5..0..0..1 %e A213960 ..0..5..5..0....1..4..0..1....0..3..1..5....1..1..6..0....1..0..1..4 %e A213960 ..5..0..3..6....1..5..3..3....0..3..4..4....4..4..1..0....0..1..3..4 %e A213960 ..0..0..4..5....0..0..1..0....3..0..4..1....0..5..2..5....0..4..6..6 %Y A213960 Cf. A213962. %K A213960 nonn %O A213960 1,1 %A A213960 _R. H. Hardin_, Jun 28 2012