A052361 Number of permutations in the symmetric group S_n such that the size of their conjugacy class is even.

0, 0, 2, 20, 104, 644, 4808, 40214, 361934, 3623084, 39889024, 478937744, 6226748384, 87175900720, 1307664018464, 20922787860974, 355687393636574, 6402373361133596, 121645097789915528, 2432901997700960264, 51090942116712179744, 1124000727209301701528

Offset

1,3

Links

Alois P. Heinz, Table of n, a(n) for n = 1..400

Maple

a:= n-> n!*(1-add((binomial(n-(n mod 2), 2*k) mod 2)/((n-2*k)!*k!*2^k),
        k=0..floor(n/2))):
seq(a(n), n=1..30);  # Alois P. Heinz, May 01 2013

Mathematica

a[n_] := n!*(1-Sum[Mod[Binomial[n-Mod[n, 2], 2*k], 2]/((n-2*k)!*k!*2^k), {k, 0, Floor[n/2]}]); Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Feb 17 2014, after Alois P. Heinz *)

Crossrefs

a(n) = n! - A088042(n).

Sequence in context: A103101 A267678 A009357 * A001884 A028477 A073077

Adjacent sequences: A052358 A052359 A052360 * A052362 A052363 A052364

Keyword

nonn

Author

Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 07 2003

Extensions

More terms from Ray Chandler, Nov 10 2003

Status

approved