A177598 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up.

1, 15, 767, 93621, 22431655, 9362799454, 6260161965339, 6298506200484865, 9087853319185940117, 18101094912700638755191

Offset

1,2

Links

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

Crossrefs

Sequence in context: A199227 A055683 A196465 * A333562 A116094 A267754

Adjacent sequences: A177595 A177596 A177597 * A177599 A177600 A177601

Keyword

nonn

Author

R. H. Hardin, May 10 2010

Extensions

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

Status

approved