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 A186906 #7 Jul 22 2025 10:34:30 %S A186906 2066505,2974946682,4813465754996,8185872059408158, %T A186906 14077041692560748494,23991605690718487651365, %U A186906 40128119810449322920431346,65662514004587268399842833783 %N A186906 Number of (n+2)X(n+2) 0..6 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order. %C A186906 Diagonal of A186915 %e A186906 Some solutions for 4X4 %e A186906 ..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0 %e A186906 ..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0 %e A186906 ..1..1..1..4....0..0..3..5....0..0..3..6....0..1..2..4....0..1..1..3 %e A186906 ..3..4..6..6....5..6..0..6....1..5..3..6....4..6..1..0....0..1..4..1 %K A186906 nonn %O A186906 1,1 %A A186906 _R. H. Hardin_ Feb 28 2011