a(n) = 2n^(n-1) - 1.A093460a(n) = 2n^(n-1) - 1.Terms a(0) =1a(1) =3a(2) =17a(3) =127a(4) =1249a(5) =15551a(6) =235297a(7) =4194303a(8) =86093441a(9) =1999999999a(10) =51874849201External referencesoeis: A093460