Dirichlet convolution of b_n = 2^(n-1) with phi(n).

Terms

a(0) =1a(1) =3a(2) =6a(3) =12a(4) =20a(5) =42a(6) =70a(7) =144a(8) =270a(9) =540a(10) =1034a(11) =2112a(12) =4108a(13) =8274a(14) =16440a(15) =32928a(16) =65552a(17) =131418a(18) =262162a(19) =524880a(20) =1048740a(21) =2098206a(22) =4194326a(23) =8391024a(24) =16777300a(25) =33558564a(26) =67109418a(27) =134226120a(28) =268435484a(29) =536888520