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 A184565 #9 Jul 22 2025 09:37:25 %S A184565 14178,993538,57374460,2943827443,136680720320,5891845723505, %T A184565 236912838360594,8847094859463950,307617377912743450, %U A184565 10100655820839334144,321449766112998837176,10305126469064160258992 %N A184565 Number of (n+2)X(n+2) 0..3 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order. %C A184565 Diagonal of A184574 %H A184565 R. H. Hardin, <a href="/A184565/b184565.txt">Table of n, a(n) for n = 1..15</a> %e A184565 Some solutions for 4X4 %e A184565 ..0..0..0..0....0..0..0..2....0..0..0..2....0..0..0..0....0..0..0..0 %e A184565 ..0..0..1..3....0..0..1..2....0..0..1..3....0..0..1..3....0..0..1..2 %e A184565 ..0..2..3..2....1..1..3..3....0..0..2..2....2..2..3..3....0..2..2..2 %e A184565 ..3..3..3..0....3..3..3..1....1..3..0..0....3..3..3..3....0..3..1..1 %K A184565 nonn %O A184565 1,1 %A A184565 _R. H. Hardin_ Jan 17 2011