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A177606
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down.
0
1, 1, 20, 1680, 369600, 167262000, 135190246573, 177591503329934, 354324970027942152
OFFSET
0,3
CROSSREFS
Cf. A014606.
Sequence in context: A177293 A266738 A177605 * A177617 A177629 A177630
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2010
STATUS
approved