A224405 Number of n X 4 0..1 arrays with rows unimodal and antidiagonals nondecreasing.

11, 56, 228, 884, 3436, 13440, 52700, 206708, 810664, 3178940, 12465596, 48881440, 191679756, 751638532, 2947419144, 11557788332, 45321842028, 177721660896, 696904347580, 2732788270804, 10716150306024, 42021505514844

Offset: 1

Author

R. H. Hardin, Apr 05 2013

Keywords

• nonn

Comments

Column 4 of A224409.

Examples

			Some solutions for n=3:
..0..0..0..0....1..1..0..0....0..0..1..1....0..1..1..1....0..1..0..0
..1..1..0..0....1..1..0..0....1..1..1..1....1..1..1..0....1..0..0..0
..1..0..0..0....1..1..0..0....1..1..1..1....1..1..1..0....0..1..0..0
		

Links

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

Crossrefs

Cf. A224409.

Formula

Empirical: a(n) = 5*a(n-1) - 5*a(n-2) + 2*a(n-3) + 4*a(n-4).

Empirical g.f.: x*(11 + x + 3*x^2 + 2*x^3) / (1 - 5*x + 5*x^2 - 2*x^3 - 4*x^4). - Colin Barker, Aug 30 2018