A177590 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, up, down, down, up, up

1, 6, 90, 2496, 110760, 7183476, 640668497, 75212295268, 11244165636152, 2085704995841392

Offset

1,2

Links

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

Crossrefs

Sequence in context: A177579 A177591 A177571 * A177577 A177572 A177583

Adjacent sequences: A177587 A177588 A177589 * A177591 A177592 A177593

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved