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 A250950 #7 Jul 23 2025 12:53:45 %S A250950 15,392,36016,11633448,13211127617,52746349035592,740399698245965774, %T A250950 36539401198968631193728,6339835499950780464168370698, %U A250950 3867371786117427361119320198505328 %N A250950 Number of (n+1)X(n+1) 0..1 arrays with no 2X2 subblock having its maximum diagonal element less than its minimum antidiagonal element. %C A250950 Diagonal of A250956 %H A250950 R. H. Hardin, <a href="/A250950/b250950.txt">Table of n, a(n) for n = 1..19</a> %e A250950 Some solutions for n=3 %e A250950 ..1..0..1..1....0..1..0..1....1..0..0..1....0..1..1..0....0..1..0..0 %e A250950 ..0..0..0..0....1..1..0..0....1..1..1..1....0..1..1..1....1..1..0..0 %e A250950 ..0..1..1..0....1..1..1..0....0..0..0..0....0..1..0..1....0..0..1..1 %e A250950 ..0..0..1..1....1..1..0..0....1..0..0..0....0..1..1..1....1..1..1..0 %K A250950 nonn %O A250950 1,1 %A A250950 _R. H. Hardin_, Nov 28 2014