A132803 Number of simple permutations in S_n, i.e., those whose "cycle graph" (or "breakpoint graph") only contains alternating cycles of length at most 3.

1, 2, 6, 16, 48, 204, 876, 3636, 18756, 105480, 561672

Offset

1,2

Links

Table of n, a(n) for n=1..11.

J.-P. Doignon and A. Labarre, On Hultman Numbers, J. Integer Seq., 10 (2007), 13 pages.

Crossrefs

Sequence in context: A214843 A272411 A151528 * A079565 A052890 A052814

Adjacent sequences: A132800 A132801 A132802 * A132804 A132805 A132806

Keyword

nonn,more

Author

Anthony Labarre, Nov 21 2007

Status

approved