A200795 Number of n X 2 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

2, 15, 178, 2614, 40148, 622645, 9676364, 150442627, 2339207390, 36372631268, 565564863676, 8794081340271, 136740955582530, 2126212947243743, 33060918081784912, 514070948321926226, 7993393871925768124

Offset

1,1

Comments

Column 2 of A200801.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 18*a(n-1) - 35*a(n-2) - 48*a(n-3) - 11*a(n-4) + 90*a(n-5) + 36*a(n-6) - 12*a(n-7) - 36*a(n-8) for n>10.

Empirical g.f.: x*(1 - x)*(2 - 19*x - 41*x^2 - 10*x^3 + 58*x^4 + 58*x^5 - 28*x^7 - 12*x^8) / ((1 - 3*x - x^2 + 2*x^4)*(1 - 15*x - 9*x^2 + 6*x^3 + 18*x^4)). - Colin Barker, Mar 02 2018

Example

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

Crossrefs

Cf. A200801.

Sequence in context: A222920 A036080 A215368 * A121427 A364340 A099709

Adjacent sequences: A200792 A200793 A200794 * A200796 A200797 A200798

Keyword

nonn

Author

R. H. Hardin, Nov 22 2011

Status

approved