A219137 Unchanging value maps: number of n X 3 binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 n X 3 array.

4, 18, 78, 331, 1400, 5949, 25277, 107353, 455938, 1936500, 8224877, 34933256, 148370893, 630171269, 2676507659, 11367850562, 48282330086, 205068091043, 870979546682, 3699285278069, 15711863292777, 66732525229601

Offset

1,1

Comments

Column 3 of A219142.

Links

R. H. Hardin, Table of n, a(n) for n = 1..106

Formula

Empirical: a(n) = 4*a(n-1) + a(n-2) + a(n-3) - 12*a(n-5) - 10*a(n-6) + 2*a(n-7) + 4*a(n-8).

Empirical g.f.: x*(4 + 2*x + 2*x^2 - 3*x^3 - 20*x^4 - 12*x^5 + 6*x^6 + 4*x^7) / (1 - 4*x - x^2 - x^3 + 12*x^5 + 10*x^6 - 2*x^7 - 4*x^8). - Colin Barker, Jul 25 2018

Example

Some solutions for n=3:
..0..0..0....1..0..0....0..0..0....0..0..0....0..0..1....0..0..0....0..0..1
..1..0..1....1..0..1....0..0..1....0..1..0....0..0..1....0..0..0....1..0..0
..0..0..0....1..1..1....1..0..0....1..1..1....0..0..0....0..0..1....0..0..1

Crossrefs

Cf. A219142.

Sequence in context: A100069 A058870 A219436 * A240342 A208309 A112619

Adjacent sequences: A219134 A219135 A219136 * A219138 A219139 A219140

Keyword

nonn

Author

R. H. Hardin, Nov 12 2012

Status

approved