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.

603, 13401, 297873, 6621219, 147178899, 3271547025, 72721157625, 1616472795339, 35931555318411, 798699904707465, 17753796965556513, 394637967071813043, 8772158730705164739, 194990789577739653441, 4334327408721425197833

Offset: 1

Author

R. H. Hardin, Nov 28 2014

Keywords

• nonn

Examples

			Some solutions for n=2:
  2 0 1   2 2 0   2 2 0   1 1 0   0 1 1   1 1 1   1 0 2
  0 2 1   2 2 1   1 1 2   2 0 1   0 2 2   2 2 0   1 2 2
  0 2 2   2 0 1   0 1 0   2 1 1   0 1 0   2 0 1   1 0 2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Column 2 of A250913.

Formula

Empirical: a(n) = 24*a(n-1) - 41*a(n-2) + 36*a(n-3).

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