If n = p_1^e_1 * ... * p_k^e_k, p_1 < ... < p_k primes, then a(n) = p_1^e_1, with a(1) = 1.

Terms

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