A221348 Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without 2-loops

0, 18, 370, 6893, 122690, 2152076, 37541550, 653557217, 11369057766, 197715942522, 3438053202520, 59781409121813, 1039472974649122, 18074147498877660, 314268989617804842, 5464430347020252629

Offset

1,2

Comments

Column 3 of A221351

Links

R. H. Hardin, Table of n, a(n) for n = 1..22

Formula

Empirical: a(n) = 26*a(n-1) -162*a(n-2) +198*a(n-3) +305*a(n-4) -794*a(n-5) +668*a(n-6) -244*a(n-7) +72*a(n-8)

Example

Some solutions for n=3
..1..3..1....1..1..0....0..1..1....0..2..1....1..1..0....1..1..0....0..3..1
..0..1..1....0..2..1....1..4..0....1..4..1....0..4..2....1..2..1....1..3..1
..0..2..0....0..3..1....1..1..0....0..0..0....0..1..0....0..3..0....0..0..0

Crossrefs

Sequence in context: A086502 A259459 A099276 * A285400 A324431 A070943

Adjacent sequences: A221345 A221346 A221347 * A221349 A221350 A221351

Keyword

nonn

Author

R. H. Hardin Jan 11 2013

Status

approved