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 A251797 #6 Jun 02 2025 10:31:51 %S A251797 36552,3352272,294088336,26787273856,2446811684440,224175608341756, %T A251797 20552060379396424,1884978485974990408,172902962249484086342, %U A251797 15861042034905778115252,1455015754461632248883532 %N A251797 Number of (n+1)X(4+1) 0..3 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251797 Column 4 of A251801 %H A251797 R. H. Hardin, <a href="/A251797/b251797.txt">Table of n, a(n) for n = 1..210</a> %e A251797 Some solutions for n=1 %e A251797 ..1..0..2..3..1....2..0..1..0..2....1..2..1..3..2....2..1..2..2..2 %e A251797 ..0..2..0..0..2....0..2..1..3..1....0..2..3..1..2....0..1..1..2..3 %K A251797 nonn %O A251797 1,1 %A A251797 _R. H. Hardin_, Dec 09 2014