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 A235672 #6 Jul 23 2025 08:43:40 %S A235672 16,380,28584,6894210,5376199876,13578805464958,111141360154581108, %T A235672 2948319928633417670416,253497281472306754538416318, %U A235672 70644048705639953560633398930712 %N A235672 Number of (n+1)X(n+1) 0..1 arrays with the difference between each 2X2 subblock maximum and minimum lexicographically nondecreasing columnwise and nonincreasing rowwise. %C A235672 Diagonal of A235679 %e A235672 Some solutions for n=3 %e A235672 ..1..1..0..1....1..0..0..1....0..0..1..0....0..0..0..1....0..1..1..0 %e A235672 ..0..0..0..0....0..0..1..1....1..0..1..0....1..0..1..0....0..0..1..0 %e A235672 ..1..0..1..0....1..0..1..0....1..0..0..0....1..1..0..1....0..1..0..1 %e A235672 ..1..0..0..0....0..1..0..0....1..1..1..0....0..0..1..0....0..1..1..0 %K A235672 nonn %O A235672 1,1 %A A235672 _R. H. Hardin_, Jan 13 2014