Total number of peaks in all permutations of 2 indistinguishable copies of 1..n.

A334776

Total number of peaks in all permutations of 2 indistinguishable copies of 1..n.

Terms

    a(0) =0a(1) =3a(2) =105a(3) =4620a(4) =283500a(5) =23700600a(6) =2610808200a(7) =367783416000

External references