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 A251273 #6 Jun 02 2025 10:20:24 %S A251273 3268,37772,273607,1457326,6247708,22806904,73607411,215673388, %T A251273 585010044,1491014836,3612638417,8399798586,18886662616,41329088816, %U A251273 88489078029,186209112216,386557846820,794103892572,1618422517619,3279033220486 %N A251273 Number of (6+1)X(n+1) 0..1 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251273 Row 6 of A251268 %H A251273 R. H. Hardin, <a href="/A251273/b251273.txt">Table of n, a(n) for n = 1..210</a> %F A251273 Empirical: a(n) = 15*a(n-1) -104*a(n-2) +442*a(n-3) -1287*a(n-4) +2717*a(n-5) -4290*a(n-6) +5148*a(n-7) -4719*a(n-8) +3289*a(n-9) -1716*a(n-10) +650*a(n-11) -169*a(n-12) +27*a(n-13) -2*a(n-14) %e A251273 Some solutions for n=2 %e A251273 ..0..0..1....0..1..1....0..1..1....0..1..1....0..0..1....0..0..1....0..0..0 %e A251273 ..0..1..1....0..1..1....0..1..1....0..0..0....0..1..1....0..1..1....0..0..1 %e A251273 ..0..0..0....1..1..1....0..1..1....1..1..1....1..0..0....1..1..1....0..0..0 %e A251273 ..1..1..1....1..1..1....1..1..1....0..1..1....0..1..1....0..0..0....0..0..1 %e A251273 ..0..0..0....1..1..1....0..1..1....1..1..1....0..0..1....1..1..1....0..0..1 %e A251273 ..0..0..1....0..0..1....0..0..1....0..0..1....0..0..1....0..1..1....1..1..1 %e A251273 ..1..1..1....0..1..0....0..0..0....0..1..1....0..1..1....1..1..1....1..1..1 %K A251273 nonn %O A251273 1,1 %A A251273 _R. H. Hardin_, Dec 01 2014