A221298 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with no occupancy greater than 2

7, 137, 2899, 63285, 1388449, 30470039, 668597561, 14670167777, 321884724335, 7062604183157, 154963457975564, 3400115973075187, 74603320698028720, 1636901638052641061, 35915920751086533900, 788045737139163431901

Offset

1,1

Comments

Column 3 of A221303

Links

R. H. Hardin, Table of n, a(n) for n = 1..209

Formula

Empirical: a(n) = 39*a(n-1) -440*a(n-2) +1503*a(n-3) -1084*a(n-4) -5364*a(n-5) -5651*a(n-6) -31458*a(n-7) -17120*a(n-8) -7253*a(n-9) -3491*a(n-10) +14148*a(n-11) -8351*a(n-12) -10211*a(n-13) +5539*a(n-14) +1198*a(n-15) -1723*a(n-16) +278*a(n-17) +396*a(n-18) -23*a(n-19) -24*a(n-20) -2*a(n-21)

Example

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

Crossrefs

Sequence in context: A058881 A100520 A221342 * A009701 A120052 A171106

Adjacent sequences: A221295 A221296 A221297 * A221299 A221300 A221301

Keyword

nonn

Author

R. H. Hardin Jan 09 2013

Status

approved