a(n) = 0 if n is 1 or a prime, otherwise a(n) = product of the proper divisors of n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =2a(4) =0a(5) =6a(6) =0a(7) =8a(8) =3a(9) =10a(10) =0a(11) =144a(12) =0a(13) =14a(14) =15a(15) =64a(16) =0a(17) =324a(18) =0a(19) =400a(20) =21a(21) =22a(22) =0a(23) =13824a(24) =5a(25) =26a(26) =27a(27) =784a(28) =0a(29) =27000