A177568 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, down, up, up

1, 6, 89, 2412, 103370, 6437048, 549450394, 61608807138, 8784739480568, 1552634332355644

Offset

1,2

Links

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

Crossrefs

Sequence in context: A101148 A355187 A100297 * A177573 A166782 A121249

Adjacent sequences: A177565 A177566 A177567 * A177569 A177570 A177571

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved