Sigma((8^n - 1)/7), where sigma(n) is the sum of positive divisors of n.

A103968

Sigma((8^n - 1)/7), where sigma(n) is the sum of positive divisors of n.

Terms

    a(0) =1a(1) =13a(2) =74a(3) =1092a(4) =4864a(5) =59200a(6) =346112a(7) =4756752a(8) =19436692a(9) =251916288a(10) =1294876800a(11) =20786304000a(12) =79541043200

External references