Dirichlet convolution of d(n) (# of divisors) with b_n=2^(n-1).

Terms

a(0) =1a(1) =4a(2) =6a(3) =15a(4) =18a(5) =48a(6) =66a(7) =154a(8) =267a(9) =552a(10) =1026a(11) =2154a(12) =4098a(13) =8328a(14) =16428a(15) =33061a(16) =65538a(17) =131676a(18) =262146a(19) =525390a(20) =1048716a(21) =2099208a(22) =4194306a(23) =8393124a(24) =16777251a(25) =33562632a(26) =67109392a(27) =134234334a(28) =268435458a(29) =536904864