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 A251274 #6 Jun 02 2025 10:20:31 %S A251274 10179,161906,1501739,9772880,49523566,208452452,760734085,2480493084, %T A251274 7386931919,20428661228,53150645617,131458741458,311732368552, %U A251274 713787172312,1587653508305,3447998356240,7343636929707,15396659787782 %N A251274 Number of (7+1)X(n+1) 0..1 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251274 Row 7 of A251268 %H A251274 R. H. Hardin, <a href="/A251274/b251274.txt">Table of n, a(n) for n = 1..210</a> %F A251274 Empirical: a(n) = 17*a(n-1) -135*a(n-2) +665*a(n-3) -2275*a(n-4) +5733*a(n-5) -11011*a(n-6) +16445*a(n-7) -19305*a(n-8) +17875*a(n-9) -13013*a(n-10) +7371*a(n-11) -3185*a(n-12) +1015*a(n-13) -225*a(n-14) +31*a(n-15) -2*a(n-16) %e A251274 Some solutions for n=2 %e A251274 ..0..1..0....0..1..0....0..0..0....0..0..1....0..0..0....0..1..1....0..0..0 %e A251274 ..0..0..1....0..0..1....0..0..1....0..1..1....1..1..1....1..0..1....0..0..0 %e A251274 ..1..1..0....1..1..1....0..1..1....0..0..1....0..1..1....0..1..1....0..0..1 %e A251274 ..0..0..1....0..0..1....0..0..1....1..1..1....0..1..1....0..1..1....1..1..0 %e A251274 ..0..0..1....0..0..0....1..1..1....0..1..1....1..1..1....0..0..1....0..0..1 %e A251274 ..0..0..1....0..1..1....0..0..0....0..1..1....1..1..1....0..0..0....0..1..1 %e A251274 ..0..0..1....0..1..1....0..1..1....0..1..1....0..0..0....0..0..1....1..1..1 %e A251274 ..0..1..0....1..0..0....1..0..0....0..0..1....0..0..0....0..0..0....0..0..1 %K A251274 nonn %O A251274 1,1 %A A251274 _R. H. Hardin_, Dec 01 2014