A207022 Number of nX6 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically

18, 324, 1350, 3726, 8280, 16038, 28224, 46260, 71766, 106560, 152658, 212274, 287820, 381906, 497340, 637128, 804474, 1002780, 1235646, 1506870, 1820448, 2180574, 2591640, 3058236, 3585150, 4177368, 4840074, 5578650, 6398676, 7305930

Offset

1,1

Comments

Column 6 of A207024

Links

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

Formula

Empirical: a(n) = (33/4)*n^4 + (45/2)*n^3 + (75/4)*n^2 - (63/2)*n.

Empirical G.f.: 18*x*(1+13*x-5*x^2+2*x^3)/(1-x)^5. [Colin Barker, May 22 2012]

Example

Some solutions for n=4
..1..1..1..1..1..1....1..0..1..0..0..1....0..1..0..1..0..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0

Crossrefs

Sequence in context: A207911 A208423 A207783 * A207366 A187381 A207109

Adjacent sequences: A207019 A207020 A207021 * A207023 A207024 A207025

Keyword

nonn

Author

R. H. Hardin Feb 14 2012

Status

approved