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A267726
Number of 3Xn arrays containing n copies of 0..3-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.
1
0, 2, 2, 30, 58, 588, 2388, 17456, 102874, 731154, 5027962, 36610288, 266876496, 1982397806, 14796809106, 111298650288, 840466993090, 6372988144620, 48466708273020, 369602842446350, 2824995007935614, 21637397279211678
OFFSET
1,2
COMMENTS
Row 3 of A267724.
LINKS
EXAMPLE
Some solutions for n=4
..0..0..0..0....0..0..2..2....0..0..1..1....0..0..0..0....0..0..2..2
..2..2..1..1....1..1..0..0....1..1..2..2....2..2..1..1....1..1..1..1
..1..1..2..2....1..1..2..2....2..2..0..0....2..2..1..1....0..0..2..2
CROSSREFS
Cf. A267724.
Sequence in context: A359998 A343172 A276821 * A371562 A309191 A372305
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 20 2016
STATUS
approved