A177591 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, up, down, down

1, 6, 90, 2482, 109476, 7045740, 623113066, 72495993816, 10736006696280, 1971973147757382

Offset

1,2

Links

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

Crossrefs

Sequence in context: A177566 A177586 A177579 * A177571 A177590 A177577

Adjacent sequences: A177588 A177589 A177590 * A177592 A177593 A177594

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved