In the prime factorization of n, increment even powers and decrement odd powers (multiplicative).

Terms

a(0) =1a(1) =1a(2) =1a(3) =8a(4) =1a(5) =1a(6) =1a(7) =4a(8) =27a(9) =1a(10) =1a(11) =8a(12) =1a(13) =1a(14) =1a(15) =32a(16) =1a(17) =27a(18) =1a(19) =8a(20) =1a(21) =1a(22) =1a(23) =4a(24) =125a(25) =1a(26) =9a(27) =8a(28) =1a(29) =1