Number of even permutations on n letters that have a root.

A338575

Number of even permutations on n letters that have a root.

Terms

    a(0) =1a(1) =3a(2) =9a(3) =45a(4) =270a(5) =1680a(6) =11340a(7) =108108a(8) =1005480a(9) =10929600a(10) =114845445a(11) =1543647105a(12) =20367547200a(13) =305087041350

External references