A275566 Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,0) (-1,2) or (0,-2) and new values introduced in order 0..2.

3, 54, 126, 294, 672, 1536, 3552, 8214, 19092, 44376, 103200, 240000, 558000, 1297350, 3015990, 7011366, 16299318, 37891014, 88085676, 204773784, 476041212, 1106661366, 2572675992, 5980747104, 13903551072, 32321836896, 75139155000

Offset: 1

Author

R. H. Hardin, Aug 01 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A275565.

Formula

Empirical: a(n) = 3*a(n-1) - 5*a(n-3) + a(n-4) + 7*a(n-5) - 5*a(n-6) + 2*a(n-8) - a(n-9) for n>10.

Empirical g.f.: 3*x*(1 + 15*x - 12*x^2 - 23*x^3 + 19*x^4 + 25*x^5 - 25*x^6 + 4*x^7 + 8*x^8 - 5*x^9) / ((1 - 3*x + 2*x^2 - x^3)*(1 - 2*x^2 + 3*x^4 - x^6)). - Colin Barker, Feb 04 2019