A177630 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down.

1, 1, 20, 1680, 369600, 167895912, 136567215720, 180834782762247, 364064983677371040

Offset

0,3

Links

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

Crossrefs

Cf. A014606.

Sequence in context: A177606 A177617 A177629 * A177294 A177615 A177616

Adjacent sequences: A177627 A177628 A177629 * A177631 A177632 A177633

Keyword

nonn,more

Author

R. H. Hardin, May 10 2010

Status

approved