Product of the numbers p such that phi(p) = n, where phi is Euler's totient function.

Terms

a(0) =2a(1) =72a(2) =1a(3) =4800a(4) =1a(5) =15876a(6) =1a(7) =3456000a(8) =1a(9) =242a(10) =1a(11) =300500928a(12) =1a(13) =1a(14) =1a(15) =2130739200a(16) =1a(17) =1052676a(18) =1a(19) =119790000a(20) =1a(21) =1058a(22) =1a(24) =1a(25) =1a(26) =1a(27) =1682a(28) =1a(29) =1922a(30) =1