A208051 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, vertical or antidiagonal neighbor (colorings ignoring permutations of colors).

2, 15, 716, 83440, 18171918, 6423127757, 3376465219485, 2486327138729353, 2454996141671330713, 3143641561804718358884, 5084413934903476204054959, 10166624612435356414640715276, 24691194409056203926713355839051

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..100 (first 20 terms from R. H. Hardin)

Example

Some solutions for n=4
..0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..0
..2..3..1....2..3..1....2..3..2....2..3..1....2..3..2....2..3..4....2..3..1
..0..2..0....0..4..5....0..4..0....1..0..2....0..1..4....0..5..0....4..5..3
..1..3..1....5..3..4....1..2..1....2..3..0....2..0..1....1..2..1....0..6..4

Crossrefs

Column 3 of A208054.

Column 6 of A216460 and column 6 of A216612.

Sequence in context: A071627 A013064 A013095 * A038017 A012993 A216331

Adjacent sequences: A208048 A208049 A208050 * A208052 A208053 A208054

Keyword

nonn

Author

R. H. Hardin, Feb 22 2012

Status

approved