A214099 Number of 0..2 colorings on an n X 7 array circular in the 7 direction with new values 0..2 introduced in row major order.

21, 322, 5068, 79968, 1262128, 19920544, 314412672, 4962482560, 78324558592, 1236223285248, 19511734746112, 307960380098560, 4860643963478016, 76717205414993920, 1210853880866258944, 19111320764068528128

Offset: 1

Author

R. H. Hardin, Jul 04 2012

Keywords

• nonn

Comments

Column 6 of A214101.

Examples

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

Links

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

Crossrefs

Cf. A214101.

Formula

Empirical: a(n) = 18*a(n-1) - 36*a(n-2) + 16*a(n-3).

Empirical g.f.: 7*x*(3 - 2*x)*(1 - 2*x) / (1 - 18*x + 36*x^2 - 16*x^3). - Colin Barker, Jul 22 2018