a(n) = Sum_{d|n} (pod(d)/d), where pod(k) is the product of the divisors of k (A007955).

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =2a(5) =9a(6) =2a(7) =12a(8) =5a(9) =13a(10) =2a(11) =155a(12) =2a(13) =17a(14) =18a(15) =76a(16) =2a(17) =336a(18) =2a(19) =415a(20) =24a(21) =25a(22) =2a(23) =13987a(24) =7a(25) =29a(26) =32a(27) =803a(28) =2a(29) =27035