Number of cycles with entries of opposite parities in all fixed-point-free involutions of {1,2,...,2n}.
A161120
Number of cycles with entries of opposite parities in all fixed-point-free involutions of {1,2,...,2n}.
Terms
- a(0) =0a(1) =1a(2) =4a(3) =27a(4) =240a(5) =2625a(6) =34020a(7) =509355a(8) =8648640a(9) =164189025a(10) =3445942500a(11) =79222218075
External references
- oeis: A161120