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A177613
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, down, down, down
0
1, 20, 1680, 365824, 163212800, 129754904960, 167412069509691, 327734823220485100
OFFSET
1,2
CROSSREFS
Sequence in context: A177612 A177618 A177624 * A177619 A177623 A177633
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved