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

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