a(n) = 2^(prime(n) - 1) - 1 where prime(n) is the n-th prime.

A098102

a(n) = 2^(prime(n) - 1) - 1 where prime(n) is the n-th prime.

Terms

    a(0) =1a(1) =3a(2) =15a(3) =63a(4) =1023a(5) =4095a(6) =65535a(7) =262143a(8) =4194303a(9) =268435455a(10) =1073741823a(11) =68719476735

External references