A214102 Number of 0..2 colorings of a 3X(n+1) array circular in the n+1 direction with new values 0..2 introduced in row major order.

9, 4, 121, 180, 2041, 5068, 37441, 121588, 722009, 2720828, 14363985, 58850116, 291217929, 1250645324, 5970338241, 26327622356, 123189300217, 551369047260, 2551171130801, 11514142774628, 52942859314409, 240066004887660

Offset: 1

Author

R. H. Hardin Jul 04 2012

Keywords

• nonn

Comments

Row 3 of A214101

Examples

			Some solutions for n=4
..0..1..0..2..1....0..1..0..1..2....0..1..2..0..1....0..1..2..0..1
..1..2..1..0..2....2..0..2..0..1....2..0..1..2..0....1..2..1..2..0
..0..1..0..2..1....0..1..0..1..2....0..1..2..1..2....2..0..2..0..1
		

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +15*a(n-2) -33*a(n-3) -22*a(n-4) +38*a(n-5) +8*a(n-6) -8*a(n-7).

Empirical: G.f. -x*(2*x^2-1)*(8*x^3-8*x^2-23*x+9) / ( (x-1)*(2*x-1)*(1+x)*(2*x^2-5*x+1)*(2*x^2+4*x+1) ). - R. J. Mathar, Jul 04 2012