A275561 Number of n X 4 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.

6, 96, 294, 1176, 4056, 15000, 54150, 196566, 714150, 2589894, 9405024, 34129350, 123887616, 449661894, 1632114294, 5924052504, 21502190976, 78045783606, 283279234776, 1028207094936, 3732040069656, 13546029168150, 49167456532134

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-2) - 8*a(n-3) - 11*a(n-4) + 17*a(n-5) - 4*a(n-6) - 6*a(n-7) + 3*a(n-8) + 2*a(n-9) - a(n-10) for n>11.

Empirical g.f.: 6*x*(1 + 13*x - 4*x^2 - 23*x^3 - 18*x^4 + 43*x^5 - 16*x^6 - 13*x^7 + 10*x^8 + 5*x^9 - 3*x^10) / ((1 - 5*x + 6*x^2 - 4*x^3 + x^4)*(1 + 2*x - x^2 - 5*x^3 - x^4 + 2*x^5 + x^6)). - Colin Barker, Feb 04 2019

Example

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

Crossrefs

Column 4 of A275565.

Sequence in context: A119627 A336825 A116158 * A116289 A116256 A275086

Adjacent sequences: A275558 A275559 A275560 * A275562 A275563 A275564

Keyword

nonn

Author

R. H. Hardin, Aug 01 2016

Status

approved