A221134 Number of nX3 arrays of occupancy after each element moves to some horizontal or vertical neighbor, with no occupancy greater than 2

2, 49, 656, 12544, 200072, 3485689, 58132316, 990486784, 16699002692, 282999528529, 4783766470826, 80965479678724, 1369496232351362, 23171487659654569, 391996208325992186, 6631958618350959364

Offset

1,1

Comments

Column 3 of A221139

Links

R. H. Hardin, Table of n, a(n) for n = 1..29

Formula

Empirical: a(n) = 21*a(n-1) -1450*a(n-3) +4782*a(n-4) -372*a(n-5) +1450*a(n-6) +69*a(n-8) +a(n-9)

Example

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

Crossrefs

Sequence in context: A028479 A189389 A001568 * A243720 A369943 A210922

Adjacent sequences: A221131 A221132 A221133 * A221135 A221136 A221137

Keyword

nonn

Author

R. H. Hardin Jan 02 2013

Status

approved