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 A238252 #6 Jul 23 2025 10:49:15 %S A238252 676,9991,284992,6683137,171041320,3320993180,64353451945, %T A238252 992794904591,15160526139045,192941078342371,2433696873065044, %U A238252 26454369332527825,285456371748779982,2719536243017821050,25745538460612968692 %N A238252 Number of (n+1)X(5+1) 0..1 arrays with 2X2 subblock sums lexicographically nondecreasing columnwise and rowwise. %C A238252 Column 5 of A238255 %H A238252 R. H. Hardin, <a href="/A238252/b238252.txt">Table of n, a(n) for n = 1..116</a> %e A238252 Some solutions for n=2 %e A238252 ..0..0..1..0..0..1....0..0..0..1..0..1....0..1..1..1..1..0....1..0..0..1..1..1 %e A238252 ..0..1..0..1..1..1....1..0..1..1..1..1....1..0..1..0..1..1....0..0..1..1..1..1 %e A238252 ..0..1..0..1..0..1....1..1..1..1..1..1....0..1..1..1..1..0....0..1..0..1..0..1 %K A238252 nonn %O A238252 1,1 %A A238252 _R. H. Hardin_, Feb 21 2014