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

1,1

Comments

Column 4 of A224409.

Links

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

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

Example

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

Crossrefs

Cf. A224409.

Sequence in context: A079547 A034264 A051946 * A201150 A114030 A071984

Adjacent sequences: A224402 A224403 A224404 * A224406 A224407 A224408

Keyword

nonn

Author

R. H. Hardin, Apr 05 2013

Status

approved