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 A266929 #6 Apr 20 2020 19:44:26 %S A266929 2,4,9,35,210,2577,68890,4605960,821453747 %N A266929 Number of n X n binary arrays with rows lexicographically nondecreasing and columns lexicographically nondecreasing and row sums nondecreasing and column sums nonincreasing. %C A266929 Diagonal of A266935. %e A266929 Some solutions for n=4 %e A266929 ..0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1....0..0..1..1 %e A266929 ..0..0..1..0....1..1..1..0....1..1..0..0....0..0..1..1....0..0..1..1 %e A266929 ..1..1..0..1....1..1..1..0....1..1..1..1....1..1..0..0....1..1..0..0 %e A266929 ..1..1..1..0....1..1..1..1....1..1..1..1....1..1..1..0....1..1..0..0 %Y A266929 Cf. A266935. %K A266929 nonn %O A266929 1,1 %A A266929 _R. H. Hardin_, Jan 06 2016