A221721 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor

8, 318, 11733, 429160, 15672482, 572137641, 20884488408, 762319022830, 27825750505059, 1015678516372760, 37073658380751658, 1353239190373176421, 49395077915916094348, 1802987762537953450798, 65811514041618097318227

Offset

1,1

Comments

Column 3 of A221723

Links

R. H. Hardin, Table of n, a(n) for n = 1..18

Formula

Empirical: a(n) = 48*a(n-1) -430*a(n-2) +313*a(n-3) +2310*a(n-4) -1178*a(n-5) -878*a(n-6) +2386*a(n-7) +364*a(n-8)

Example

Some solutions for n=3
..1..2..0....2..1..0....0..2..3....1..0..2....1..2..2....1..1..0....2..1..0
..0..1..0....1..1..0....0..2..1....2..1..0....1..1..1....0..0..3....0..2..3
..0..5..0....0..2..2....0..1..0....1..1..1....1..0..0....1..2..1....0..1..0

Crossrefs

Sequence in context: A264661 A231781 A220618 * A079504 A282621 A300189

Adjacent sequences: A221718 A221719 A221720 * A221722 A221723 A221724

Keyword

nonn

Author

R. H. Hardin Jan 22 2013

Status

approved