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
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..400
Crossrefs
a(n) = n! - A088042(n).
Programs
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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 *)
Extensions
More terms from Ray Chandler, Nov 10 2003