A275085 - OEIS

A275085

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

3, 36, 192, 1024, 5440, 29120, 155904, 834176, 4463424, 23883904, 127801600, 683853952, 3659249536, 19580378368, 104773120768, 560632993280, 2999904734464, 16052263263232, 85894445131264, 459614672161280

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) + 4*a(n-2) + 14*a(n-3) + 18*a(n-4) - 8*a(n-5) + 16*a(n-6) + 80*a(n-7) - 32*a(n-8) - 64*a(n-9) for n>10.

Empirical g.f.: x*(3 + 24*x + 36*x^2 + 70*x^3 + 18*x^4 - 48*x^5 + 112*x^6 + 208*x^7 - 160*x^8 - 192*x^9) / (1 - 4*x - 4*x^2 - 14*x^3 - 18*x^4 + 8*x^5 - 16*x^6 - 80*x^7 + 32*x^8 + 64*x^9). - Colin Barker, Jan 31 2019

EXAMPLE

Some solutions for n=4:

..0..1..2. .0..0..1. .0..1..1. .0..0..1. .0..0..1. .0..0..1. .0..0..1

..2..2..1. .0..0..2. .1..1..2. .0..0..1. .0..1..2. .1..0..2. .2..0..1

..2..2..0. .2..2..1. .1..1..0. .0..1..1. .2..1..1. .1..2..2. .0..2..1

..0..1..1. .0..2..1. .2..0..0. .1..2..2. .1..1..0. .1..0..2. .1..1..2

CROSSREFS

Column 3 of A275090.

Sequence in context: A068619 A247768 A168075 * A303152 A188891 A073992

Adjacent sequences: A275082 A275083 A275084 * A275086 A275087 A275088

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 16 2016

STATUS

approved