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 A254456 #6 Jul 23 2025 14:41:51 %S A254456 6440848,289945200,14531913928,623402653056,25559706957728, %T A254456 1041397026476012,41728495959588032,1663022535691018136, %U A254456 66242299786253394624,2638365158866570322184,105052207003477821889696 %N A254456 Number of (n+2)X(7+2) 0..1 arrays with every 3X3 subblock diagonal maximum minus antidiagonal median nondecreasing horizontally and vertically. %C A254456 Column 7 of A254457 %H A254456 R. H. Hardin, <a href="/A254456/b254456.txt">Table of n, a(n) for n = 1..47</a> %e A254456 Some solutions for n=1 %e A254456 ..0..0..0..0..1..0..1..1..0....0..0..0..0..0..0..0..0..0 %e A254456 ..0..0..1..1..0..1..0..0..0....1..1..0..0..0..0..1..0..1 %e A254456 ..0..1..0..1..1..0..0..0..0....1..1..1..0..0..0..1..1..1 %K A254456 nonn %O A254456 1,1 %A A254456 _R. H. Hardin_, Jan 30 2015