cp's OEIS Frontend

A250907 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.

%I A250907 #10 Nov 23 2018 21:17:54
%S A250907 603,13401,297873,6621219,147178899,3271547025,72721157625,
%T A250907 1616472795339,35931555318411,798699904707465,17753796965556513,
%U A250907 394637967071813043,8772158730705164739,194990789577739653441,4334327408721425197833
%N A250907 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.
%H A250907 R. H. Hardin, <a href="/A250907/b250907.txt">Table of n, a(n) for n = 1..210</a>
%F A250907 Empirical: a(n) = 24*a(n-1) - 41*a(n-2) + 36*a(n-3).
%F A250907 Empirical g.f.: 9*x*(67 - 119*x + 108*x^2) / (1 - 24*x + 41*x^2 - 36*x^3). - _Colin Barker_, Nov 23 2018
%e A250907 Some solutions for n=2:
%e A250907   2 0 1   2 2 0   2 2 0   1 1 0   0 1 1   1 1 1   1 0 2
%e A250907   0 2 1   2 2 1   1 1 2   2 0 1   0 2 2   2 2 0   1 2 2
%e A250907   0 2 2   2 0 1   0 1 0   2 1 1   0 1 0   2 0 1   1 0 2
%Y A250907 Column 2 of A250913.
%K A250907 nonn
%O A250907 1,1
%A A250907 _R. H. Hardin_, Nov 28 2014