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 A251067 #6 Jun 02 2025 10:18:04 %S A251067 2167,31895,320950,2482824,15857764,87634164,432850109,1956154249, %T A251067 8230778879,32676321575,123677283286,449978960436,1584259322792, %U A251067 5426858063472,18167839282369,59663626761417,192807960435551 %N A251067 Number of (3+1)X(n+1) 0..2 arrays with no 2X2 subblock having x11-x00 less than x10-x01. %C A251067 Row 3 of A251065 %H A251067 R. H. Hardin, <a href="/A251067/b251067.txt">Table of n, a(n) for n = 1..210</a> %F A251067 Empirical: a(n) = 30*a(n-1) -425*a(n-2) +3782*a(n-3) -23721*a(n-4) +111526*a(n-5) -408077*a(n-6) +1190790*a(n-7) -2816743*a(n-8) +5459714*a(n-9) -8729643*a(n-10) +11551618*a(n-11) -12652835*a(n-12) +11438610*a(n-13) -8481295*a(n-14) +5104082*a(n-15) -2453580*a(n-16) +919720*a(n-17) -259024*a(n-18) +51552*a(n-19) -6464*a(n-20) +384*a(n-21) %e A251067 Some solutions for n=2 %e A251067 ..1..1..1....0..1..2....1..1..1....1..2..1....0..1..0....0..2..2....2..2..1 %e A251067 ..0..0..0....0..1..1....0..1..1....1..0..1....0..0..2....1..1..1....1..1..2 %e A251067 ..2..2..2....0..1..2....2..1..1....1..2..2....1..1..1....0..0..2....1..2..2 %e A251067 ..0..0..0....1..2..1....1..2..2....0..2..2....0..1..1....1..1..1....2..1..2 %K A251067 nonn %O A251067 1,1 %A A251067 _R. H. Hardin_, Nov 29 2014