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A177633
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, down, up, up, up
0
1, 20, 1680, 368168, 166221670, 134195139015, 176210700176028, 351584685612733980
OFFSET
1,2
CROSSREFS
Sequence in context: A177613 A177619 A177623 * A177634 A177293 A266738
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved