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A177616
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down, down.
0
1, 1, 20, 1680, 369600, 168168000, 137150254800, 182209829636934, 368221858096998960
OFFSET
0,3
CROSSREFS
Cf. A014606.
Sequence in context: A177630 A177294 A177615 * A177295 A177635 A177296
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 10 2010
STATUS
approved