A275561 - OEIS

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

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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: A336825 A376155 A116158 * A116289 A116256 A275086

Adjacent sequences: A275558 A275559 A275560 * A275562 A275563 A275564

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 01 2016

STATUS

approved