A221226 Number of n X 2 arrays of occupancy after each element moves to some king-move neighbor, with no occupancy greater than 2.

1, 19, 137, 1033, 7877, 60223, 460713, 3524857, 26968225, 206327811, 1578551849, 12076946305, 92396113725, 706885768959, 5408092980713, 41375064828945, 316543208763529, 2421738125898019, 18527690050695513, 141747473284341977

Offset

1,2

Comments

Column 2 of A221229.

Links

R. H. Hardin, Table of n, a(n) for n = 1..65

Formula

Empirical: a(n) = 15*a(n-1) - 71*a(n-2) + 123*a(n-3) - 78*a(n-4) + 14*a(n-5) - 12*a(n-6) + 8*a(n-7).

Empirical g.f.: x*(1 + 4*x - 77*x^2 + 204*x^3 - 150*x^4 + 28*x^5 + 8*x^6) / (1 - 15*x + 71*x^2 - 123*x^3 + 78*x^4 - 14*x^5 + 12*x^6 - 8*x^7). - Colin Barker, Mar 14 2018

Example

Some solutions for n=3:
..0..2....1..2....1..1....2..1....2..2....1..2....0..1....1..1....0..0....1..0
..2..0....0..1....0..2....0..2....1..1....0..2....1..1....1..0....2..2....1..2
..1..1....1..1....1..1....0..1....0..0....1..0....1..2....2..1....0..2....0..2

Crossrefs

Cf. A221229.

Sequence in context: A213122 A211092 A142746 * A139902 A140624 A244505

Adjacent sequences: A221223 A221224 A221225 * A221227 A221228 A221229

Keyword

nonn

Author

R. H. Hardin, Jan 05 2013

Status

approved