A177588 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, up, up, up, up

1, 6, 90, 2520, 113160, 7441949, 674077493, 80453033424, 12236281595093, 2310183602289482

Offset

1,2

Links

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

Crossrefs

Sequence in context: A177564 A177565 A177576 * A177589 A177285 A177574

Adjacent sequences: A177585 A177586 A177587 * A177589 A177590 A177591

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved