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 A185468 #8 Jul 22 2025 09:47:42 %S A185468 1169,21834,308692,3959167,46410729,493061605,4845252741,45945546278, %T A185468 443977171724,4605035061272,52677880798334,659609567593921, %U A185468 8802320668197926,122014363451316512,1727721369461575287 %N A185468 Number of (n+2)X(n+2) 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order. %C A185468 Diagonal of A185477 %H A185468 R. H. Hardin, <a href="/A185468/b185468.txt">Table of n, a(n) for n = 1..26</a> %e A185468 Some solutions for 4X4 %e A185468 ..0..0..0..2....0..0..0..0....0..0..2..2....0..0..0..2....0..0..1..1 %e A185468 ..0..0..1..2....1..1..1..2....0..0..2..2....0..1..2..2....0..1..1..1 %e A185468 ..0..1..1..2....1..1..2..0....0..0..2..2....0..2..1..1....0..1..1..2 %e A185468 ..1..2..2..0....1..1..2..1....1..1..1..2....0..2..1..1....2..2..2..0 %K A185468 nonn %O A185468 1,1 %A A185468 _R. H. Hardin_ Jan 28 2011