a(n) = Product_{d|n, d>1} prime(gcd(d,n/d)).

Terms

a(0) =1a(1) =2a(2) =2a(3) =6a(4) =2a(5) =8a(6) =2a(7) =18a(8) =10a(9) =8a(10) =2a(11) =72a(12) =2a(13) =8a(14) =8a(15) =126a(16) =2a(17) =200a(18) =2a(19) =72a(20) =8a(21) =8a(22) =2a(23) =648a(24) =22a(25) =8a(26) =50a(27) =72a(28) =2a(29) =128