A221402 Number of 3Xn arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no 2-loops and with no occupancy greater than 2

0, 7, 30, 2110, 26374, 681300, 11554698, 239213277, 4414861636, 86099730502, 1625526991148, 31160102911062, 591775127780270, 11285743215972044, 214648325661089776, 4087126318623042490, 77761170034232040294

Offset

1,2

Comments

Row 3 of A221400

Links

R. H. Hardin, Table of n, a(n) for n = 1..20

Example

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

Crossrefs

Sequence in context: A196338 A196315 A156347 * A065916 A122654 A184121

Adjacent sequences: A221399 A221400 A221401 * A221403 A221404 A221405

Keyword

nonn

Author

R. H. Hardin Jan 15 2013

Status

approved