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A208347
Number of nX2 0..3 arrays with new values 0..3 introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors)
2
2, 15, 100, 868, 7780, 69988, 629860, 5668708, 51018340, 459165028, 4132485220, 37192366948, 334731302500, 3012581722468, 27113235502180, 244019119519588, 2196172075676260, 19765548681086308, 177889938129776740
OFFSET
1,1
COMMENTS
Column 2 of A208353
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) -9*a(n-2) for n>4
EXAMPLE
Some solutions for n=4
..0..0....0..1....0..0....0..0....0..0....0..0....0..1....0..0....0..0....0..0
..0..0....1..0....0..0....0..0....1..0....1..1....1..2....0..0....0..0....1..0
..1..1....0..1....1..2....1..1....1..1....1..1....0..1....1..1....1..2....1..1
..2..2....1..2....3..2....1..1....1..0....0..0....0..0....1..2....1..3....1..2
CROSSREFS
Sequence in context: A376922 A258390 A027080 * A293045 A372264 A081018
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 25 2012
STATUS
approved