A221196 - OEIS

A221196

Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.

2, 10, 46, 212, 976, 4492, 20672, 95128, 437752, 2014400, 9269632, 42655888, 196288736, 903257824, 4156502752, 19126892096, 88015820416, 405020564416, 1863774679808, 8576493051520, 39466269101440, 181611106939904

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 3 of A221200.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..33

FORMULA

Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 2*a(n-3).

Empirical g.f.: 2*x*(1 - x - x^2) / (1 - 6*x + 6*x^2 + 2*x^3). - Colin Barker, Aug 04 2018

EXAMPLE

Some solutions for n=3:

..0..2..0....0..2..0....1..2..0....1..2..1....1..2..1....1..2..0....0..2..1

..1..2..2....0..2..2....0..2..1....1..2..0....0..2..1....1..2..0....0..2..2

..0..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..1....0..2..0

CROSSREFS

Cf. A221200.

Sequence in context: A290923 A106709 A204091 * A137193 A006213 A137635

Adjacent sequences: A221193 A221194 A221195 * A221197 A221198 A221199

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 04 2013

STATUS

approved