A208562 Number of n X 3 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than one of its immediate leftward or upward or left-upward diagonal neighbors.

5, 68, 1059, 16608, 260856, 4098492, 64398564, 1011891888, 15899856696, 249834571632, 3925652965344, 61683823050048, 969238512405216, 15229654196873472, 239303704937730624, 3760181449823927808

Offset

1,1

Comments

Column 3 of A208567.

Links

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

Formula

Empirical: a(n) = 22*a(n-1) - 110*a(n-2) + 180*a(n-3) - 60*a(n-4) for n>5.

Empirical g.f.: x*(5 - 42*x + 113*x^2 - 110*x^3 + 30*x^4) / (1 - 22*x + 110*x^2 - 180*x^3 + 60*x^4). - Colin Barker, Jul 05 2018

Example

Some solutions for n=4:
..0..0..0....0..0..1....0..0..0....0..0..0....0..0..1....0..0..1....0..1..2
..1..1..1....2..1..2....0..1..1....0..1..2....2..1..2....2..1..0....1..2..0
..1..0..0....2..0..0....1..2..0....2..0..1....2..0..2....2..0..1....0..1..0
..1..2..2....0..2..1....1..2..1....0..1..0....2..0..1....2..0..2....2..0..1

Crossrefs

Cf. A208567.

Sequence in context: A281558 A165396 A029812 * A093120 A264697 A319465

Adjacent sequences: A208559 A208560 A208561 * A208563 A208564 A208565

Keyword

nonn

Author

R. H. Hardin, Feb 28 2012

Status

approved