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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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 21 2012
STATUS
approved