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A266682
Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its northwest or northeast neighbor modulo 3 and the upper left element equal to 0.
2
2, 5, 15, 59, 257, 1205, 5879, 29693, 153097, 806375, 4307317, 23313947, 127420533, 702562447, 3900415155, 21786817517, 122309555899, 689707853981, 3904123962093, 22174631940293, 126322762595339, 721552901977497
OFFSET
1,1
COMMENTS
Row 3 of A266681.
LINKS
EXAMPLE
Some solutions for n=4
..0..2..1..2....0..2..1..2....0..2..0..1....0..0..2..0....0..1..2..1
..1..0..1..0....2..0..2..1....1..2..1..2....0..2..2..1....1..2..0..2
..2..1..2..0....0..1..0..1....2..0..1..0....1..2..1..1....1..0..2..0
CROSSREFS
Cf. A266681.
Sequence in context: A048192 A078792 A208808 * A325575 A332248 A030934
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 02 2016
STATUS
approved