A177589 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down

1, 6, 90, 2520, 113256, 7457040, 676387059, 80853167472, 12317360601240, 2329487321538500

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Crossrefs

Sequence in context: A177565 A177576 A177588 * A177285 A177574 A177575

Adjacent sequences: A177586 A177587 A177588 * A177590 A177591 A177592

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved