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

Terms

a(0) =1a(1) =2a(2) =2a(3) =6a(4) =3a(5) =20a(6) =2a(7) =42a(8) =10a(9) =66a(10) =2a(11) =660a(12) =2a(13) =20a(14) =42a(15) =546a(16) =13a(17) =1700a(18) =2a(19) =3762a(20) =12a(21) =20a(22) =5a(23) =106260a(24) =6a(25) =20a(26) =110a(27) =660a(28) =5a(29) =106260