A275140 Number of n X 6 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,-2) or (0,-1) and new values introduced in order 0..2.

16, 432, 1216, 6464, 32384, 165568, 841536, 4283968, 21800000, 110943552, 564600384, 2873300800, 14622480448, 74415076672, 378704836160, 1927261993792, 9808004727872, 49913793159488, 254015655387712, 1292707868694336

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 10*a(n-2) + 4*a(n-3) - 4*a(n-4) for n>6.

Empirical g.f.: 16*x*(1 + 24*x - 15*x^2 - 98*x^3 - 52*x^4 + 40*x^5) / (1 - 3*x - 10*x^2 - 4*x^3 + 4*x^4). - Colin Barker, Jan 31 2019

Example

Some solutions for n=5:
..0..1..2..1..0..2. .0..1..2..0..1..2. .0..1..2..1..0..2. .0..1..2..0..1..0
..2..1..2..0..1..0. .0..1..2..0..1..2. .2..1..2..0..1..2. .0..1..2..0..1..2
..2..0..1..2..1..2. .2..0..1..2..1..2. .1..0..1..2..0..2. .2..0..1..2..0..1
..2..0..1..2..0..1. .1..0..1..2..0..1. .1..2..0..2..0..1. .1..2..1..2..0..1
..0..2..0..1..0..1. .0..2..0..1..2..0. .0..2..0..1..2..1. .2..1..0..1..0..1

Crossrefs

Column 6 of A275142.

Sequence in context: A322713 A359642 A275035 * A274731 A111921 A118994

Adjacent sequences: A275137 A275138 A275139 * A275141 A275142 A275143

Keyword

nonn

Author

R. H. Hardin, Jul 17 2016

Status

approved