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A177589
Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down
0
1, 6, 90, 2520, 113256, 7457040, 676387059, 80853167472, 12317360601240, 2329487321538500
OFFSET
1,2
CROSSREFS
Sequence in context: A177565 A177576 A177588 * A177285 A177574 A177575
KEYWORD
nonn
AUTHOR
R. H. Hardin May 10 2010
STATUS
approved