a(n) = Sum_{d|n} A007955(d) where A007955(m) = product of divisors of m.

Terms

a(0) =1a(1) =3a(2) =4a(3) =11a(4) =6a(5) =42a(6) =8a(7) =75a(8) =31a(9) =108a(10) =12a(11) =1778a(12) =14a(13) =206a(14) =234a(15) =1099a(16) =18a(17) =5901a(18) =20a(19) =8116a(20) =452a(21) =498a(22) =24a(23) =333618a(24) =131a(25) =692a(26) =760a(27) =22166a(28) =30a(29) =810372