A177600 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down.

1, 1, 20, 1680, 354624, 151213748, 114062310060, 139028830444866, 256400413791435360, 680598969845995094212, 2500271405904975564019712

Offset

0,3

Links

Table of n, a(n) for n=0..10.

Crossrefs

Cf. A014606.

Sequence in context: A177292 A266737 A177599 * A177607 A177612 A177618

Adjacent sequences: A177597 A177598 A177599 * A177601 A177602 A177603

Keyword

nonn

Author

R. H. Hardin, May 10 2010

Extensions

a(9)-a(10) from Alois P. Heinz, Nov 02 2013

Status

approved