a(n) = Sum_{i=1..n} (prime(i)^n - 1)/(prime(i) - 1).

A124271

a(n) = Sum_{i=1..n} (prime(i)^n - 1)/(prime(i) - 1).

Terms

    a(0) =1a(1) =7a(2) =51a(3) =611a(4) =19839a(5) =603331a(6) =32981935a(7) =1469991559a(8) =108336139407

External references