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A177630
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down.
0
1, 1, 20, 1680, 369600, 167895912, 136567215720, 180834782762247, 364064983677371040
OFFSET
0,3
CROSSREFS
Cf. A014606.
Sequence in context: A177606 A177617 A177629 * A177294 A177615 A177616
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, May 10 2010
STATUS
approved