A207865 Number of n X 3 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).

2, 34, 2052, 278982, 68162042, 26419793726, 15002771641712, 11807624578397830, 12361734324171045410, 16679505289611340233906, 28284296659644702241447604, 59055088260515144420128767278, 149249218670114328150978145481610

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..190 (terms 1..20 from R. H. Hardin)

Example

Some solutions for n=5
..0..1..2....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0
..2..0..1....1..0..1....1..0..1....1..0..1....1..0..2....1..0..1....1..2..1
..0..1..0....0..1..0....0..1..0....0..1..0....0..1..3....0..1..0....2..0..2
..1..0..1....1..0..1....1..0..1....1..2..1....1..0..1....2..0..1....0..1..0
..0..1..0....0..2..0....2..1..0....0..1..0....0..1..2....0..1..0....1..0..1

Crossrefs

Column 3 of A207868.

Sequence in context: A198977 A198718 A198909 * A216082 A165938 A255434

Adjacent sequences: A207862 A207863 A207864 * A207866 A207867 A207868

Keyword

nonn

Author

R. H. Hardin, Feb 21 2012

Status

approved