Number of elements of S_n having order n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =240a(6) =720a(7) =5040a(8) =40320a(9) =514080a(10) =3628800a(11) =80166240a(12) =479001600a(13) =6797831040a(14) =93774320640