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 A254160 #7 Jul 23 2025 14:28:36 %S A254160 512,23660,1553720,191190272,47722312832,24789263869340, %T A254160 27196332026497280,62670987439073417464,306649596390478314360688, %U A254160 3185451673330281289722851308,70105876620029167895782015020688 %N A254160 Number of (n+2)X(n+2) 0..1 arrays with every 3X3 subblock diagonal maximum minus antidiagonal median nondecreasing horizontally, vertically and ne-to-sw antidiagonally. %C A254160 Diagonal of A254168 %H A254160 R. H. Hardin, <a href="/A254160/b254160.txt">Table of n, a(n) for n = 1..13</a> %e A254160 Some solutions for n=2 %e A254160 ..1..0..0..1....0..0..1..1....0..0..1..1....1..1..1..0....1..1..0..1 %e A254160 ..0..1..1..0....0..1..1..1....0..1..1..0....1..0..1..1....1..1..0..1 %e A254160 ..1..0..0..0....1..1..1..0....1..1..1..1....1..1..1..0....1..1..1..1 %e A254160 ..0..0..0..1....0..0..0..1....1..0..1..0....1..0..1..0....1..0..0..1 %K A254160 nonn %O A254160 1,1 %A A254160 _R. H. Hardin_, Jan 26 2015