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

1,1

Links

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

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

Example

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

Crossrefs

Row 3 of A275565.

Sequence in context: A092448 A344424 A045481 * A068380 A174782 A345074

Adjacent sequences: A275563 A275564 A275565 * A275567 A275568 A275569

Keyword

nonn

Author

R. H. Hardin, Aug 01 2016

Status

approved