a(1) = 0; for n > 1, a(n) = Product_{d|n, 1 < d < n} prime(A305788(d)-1).

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =1a(5) =4a(6) =1a(7) =6a(8) =2a(9) =6a(10) =1a(11) =60a(12) =1a(13) =4a(14) =6a(15) =42a(16) =1a(17) =100a(18) =1a(19) =198a(20) =4a(21) =4a(22) =1a(23) =4620a(24) =3a(25) =4a(26) =10a(27) =60a(28) =1a(29) =4620