login
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).
4
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 22 2012
STATUS
approved