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 A202651 #20 Jul 11 2021 03:41:26 %S A202651 2,3,8,4,52,126,5,184,8460,10016,6,480,143028,14394092,3648810,7,1040, %T A202651 1217196,1960824272,231197740500,5616280768,8,1988,6835050, %U A202651 82673548892,443471777729100 %N A202651 Table read by downward antidiagonals: T(n,k) is the number of n X n 0..k arrays with no row or column sum equal to the previous one. %C A202651 Table starts %C A202651 2. 3, 4, 5, 6, 7, 8, ... %C A202651 8, 52, 184, 480, 1040, 1988, ... %C A202651 126, 8460, 143028, 1217196, 6835050, ... %C A202651 10016, 14394092, 1960824272, 82673548892, ... %C A202651 3648810, 231197740500, 443471777729100, ... %C A202651 5616280768, ... %e A202651 Some solutions for n=3, k=3: %e A202651 2 0 3 2 0 1 0 0 3 0 1 3 0 0 3 1 2 1 2 0 3 %e A202651 1 0 0 0 1 3 3 0 2 1 2 3 0 3 2 0 2 3 2 0 0 %e A202651 3 1 0 2 0 0 0 0 1 0 1 3 2 1 0 0 2 1 0 1 3 %Y A202651 Rows n=2..4: A035288, A202652, A202653. %Y A202651 Column 3 is A202631. %K A202651 nonn,tabl,more %O A202651 1,1 %A A202651 _R. H. Hardin_, Dec 22 2011