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A177582
Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, down, up, up, up
0
1, 6, 90, 2510, 112020, 7307874, 655845094, 77496572328, 11662893335890, 2177988280932500
OFFSET
1,2
CROSSREFS
Sequence in context: A177572 A177583 A177578 * A177592 A177593 A132467
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved