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 A251059 #6 Jun 02 2025 10:17:14 %S A251059 222,2740,31895,379440,4499219,53420941,634161915,7528829372, %T A251059 89381885986,1061143804301,12597914485712,149562686271463, %U A251059 1775611051165233,21080088759507993,250263221101743326,2971129803512557016 %N A251059 Number of (n+1)X(2+1) 0..2 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251059 Column 2 of A251065 %H A251059 R. H. Hardin, <a href="/A251059/b251059.txt">Table of n, a(n) for n = 1..210</a> %F A251059 Empirical: a(n) = 14*a(n-1) -12*a(n-2) -184*a(n-3) +281*a(n-4) +477*a(n-5) -863*a(n-6) -69*a(n-7) +517*a(n-8) -106*a(n-9) -80*a(n-10) +24*a(n-11) %e A251059 Some solutions for n=3 %e A251059 ..2..0..0....2..1..2....1..2..1....0..2..2....0..0..0....0..0..2....0..0..2 %e A251059 ..0..2..2....0..2..1....0..0..1....1..0..1....1..2..2....1..2..2....0..2..0 %e A251059 ..2..0..2....0..0..2....0..1..1....1..2..2....0..0..1....1..2..2....0..0..2 %e A251059 ..0..2..1....0..1..2....0..1..1....0..1..2....0..1..1....2..1..2....1..2..0 %K A251059 nonn %O A251059 1,1 %A A251059 _R. H. Hardin_, Nov 29 2014