a(n) = (n^(n-1) - 1)/(n-1) for n>1, a(1) = 0.

A060072

a(n) = (n^(n-1) - 1)/(n-1) for n>1, a(1) = 0.

Terms

    a(0) =0a(1) =1a(2) =4a(3) =21a(4) =156a(5) =1555a(6) =19608a(7) =299593a(8) =5380840a(9) =111111111a(10) =2593742460a(11) =67546215517

External references