A232303 Number of n X 2 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally, vertically or antidiagonally.

3, 37, 257, 1915, 14223, 105411, 781873, 5798587, 43004317, 318935945, 2365343683, 17542244471, 130099628443, 964865884537, 7155794283827, 53069957831125, 393585996554193, 2918976065097931, 21648181955586463, 160550745032206387

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 9*a(n-2) + 11*a(n-3) - a(n-4) + 16*a(n-5).

Empirical g.f.: x*(3 + 19*x + 8*x^2 + 7*x^3 + 16*x^4) / (1 - 6*x - 9*x^2 - 11*x^3 + x^4 - 16*x^5). - Colin Barker, Oct 04 2018

Example

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

Crossrefs

Column 2 of A232309.

Sequence in context: A106995 A120076 A119938 * A196978 A197163 A326246

Adjacent sequences: A232300 A232301 A232302 * A232304 A232305 A232306

Keyword

nonn

Author

R. H. Hardin, Nov 22 2013

Status

approved