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 A251806 #6 Jun 02 2025 10:32:51 %S A251806 27278035,12140516092,2255553135793,224175608341756,13902663302194715, %T A251806 596244004665414586,19010586449609604592,475164885888410556180, %U A251806 9691434735916414155212,166393734233809655597676 %N A251806 Number of (6+1)X(n+1) 0..3 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251806 Row 6 of A251801 %H A251806 R. H. Hardin, <a href="/A251806/b251806.txt">Table of n, a(n) for n = 1..35</a> %e A251806 Some solutions for n=1 %e A251806 ..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0 %e A251806 ..0..0....0..0....0..2....0..2....0..2....0..2....0..0....0..0....0..2....0..0 %e A251806 ..0..2....2..2....2..2....0..0....0..0....0..2....2..2....0..2....0..2....0..0 %e A251806 ..2..3....3..3....2..3....0..2....0..2....2..0....0..2....1..2....1..2....0..2 %e A251806 ..3..2....3..3....2..3....3..3....3..2....1..3....2..1....0..2....3..3....1..2 %e A251806 ..0..1....0..3....1..2....2..2....0..2....2..1....0..1....0..1....1..2....0..3 %e A251806 ..2..2....3..1....2..1....0..3....0..1....0..2....2..1....3..3....3..3....2..3 %K A251806 nonn %O A251806 1,1 %A A251806 _R. H. Hardin_, Dec 09 2014