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A177617
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down, up.
0
1, 1, 20, 1680, 369600, 167510862, 135702841152, 178756061502340, 357729925926146006
OFFSET
0,3
CROSSREFS
Cf. A014606.
Sequence in context: A266738 A177605 A177606 * A177629 A177630 A177294
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2010
STATUS
approved