A232145 Number of n X 2 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally, diagonally or antidiagonally.

3, 23, 145, 887, 5487, 33957, 210039, 1299219, 8036625, 49712291, 307505983, 1902144221, 11766121259, 72781867263, 450207854133, 2784857267659, 17226332081291, 106557172756085, 659132252427443, 4077203954957651

Offset

1,1

Comments

Column 2 of A232149.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 5*a(n-1) + 6*a(n-2) + 8*a(n-3) + 3*a(n-4) - 8*a(n-5) - 5*a(n-6).

Empirical g.f.: x*(3 + 8*x + 12*x^2 - 11*x^4 - 5*x^5) / (1 - 5*x - 6*x^2 - 8*x^3 - 3*x^4 + 8*x^5 + 5*x^6). - Colin Barker, Mar 19 2018

Example

Some solutions for n=6:
..2..2....1..2....1..2....0..1....2..1....1..2....1..2....0..2....1..0....0..1
..0..2....2..0....2..1....2..2....2..1....2..2....0..1....2..1....1..2....2..1
..2..1....0..1....0..1....2..2....1..0....2..1....2..2....0..1....0..2....2..1
..0..0....1..0....1..2....1..1....1..2....1..2....1..0....2..1....2..1....0..0
..1..2....2..2....1..2....2..1....2..1....2..2....2..1....2..1....2..1....1..2
..1..2....1..2....1..2....0..2....2..1....2..1....0..2....1..2....0..2....2..0

Crossrefs

Cf. A232149.

Sequence in context: A089950 A198797 A057835 * A079755 A197176 A264461

Adjacent sequences: A232142 A232143 A232144 * A232146 A232147 A232148

Keyword

nonn

Author

R. H. Hardin, Nov 19 2013

Status

approved