Number of inversions in all fixed-point-free involutions of {1,2,...,2n}.
A161124
Number of inversions in all fixed-point-free involutions of {1,2,...,2n}.
Terms
- a(0) =0a(1) =1a(2) =12a(3) =135a(4) =1680a(5) =23625a(6) =374220a(7) =6621615a(8) =129729600a(9) =2791213425a(10) =65472907500
External references
- oeis: A161124