Auxiliary sequence for calculation of number of even permutations of degree n and order exactly 4.

A051685

Auxiliary sequence for calculation of number of even permutations of degree n and order exactly 4.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =-6a(4) =-30a(5) =0a(6) =420a(7) =2100a(8) =6804a(9) =-20160a(10) =-376200a(11) =-2102760a(12) =-6606600a(13) =53237184a(14) =965306160a(15) =5941244400a(16) =12774059760a(17) =-305998041600

External references