A177606 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, down.

1, 1, 20, 1680, 369600, 167262000, 135190246573, 177591503329934, 354324970027942152

Offset

0,3

Links

Table of n, a(n) for n=0..8.

Crossrefs

Cf. A014606.

Sequence in context: A177293 A266738 A177605 * A177617 A177629 A177630

Adjacent sequences: A177603 A177604 A177605 * A177607 A177608 A177609

Keyword

nonn

Author

R. H. Hardin, May 10 2010

Status

approved