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 A267239 #6 Apr 20 2020 19:44:48 %S A267239 2,7,42,567,20040,2093467,683027146,723576702570,2549735632656528, %T A267239 30465608408449993885,1250919952257037350168062, %U A267239 178764247753852768666003981113,89752660973687899647122735126286078 %N A267239 Number of n X n binary arrays with row sums nondecreasing and columns lexicographically nondecreasing. %C A267239 Diagonal of A267245. %e A267239 Some solutions for n=4 %e A267239 ..0..0..0..1....0..0..0..1....0..0..1..1....0..0..0..1....0..0..0..1 %e A267239 ..0..1..1..0....0..0..0..1....0..1..0..1....0..0..1..1....0..0..1..1 %e A267239 ..1..0..1..0....0..0..1..1....1..1..0..0....0..1..0..1....1..1..1..0 %e A267239 ..1..1..1..1....1..1..1..0....1..1..0..0....1..1..1..0....1..1..0..1 %Y A267239 Cf. A267245. %K A267239 nonn %O A267239 1,1 %A A267239 _R. H. Hardin_, Jan 12 2016