Negate primes in factorization of n.

Terms

a(0) =1a(1) =-2a(2) =-3a(3) =4a(4) =-5a(5) =6a(6) =-7a(7) =-8a(8) =9a(9) =10a(10) =-11a(11) =-12a(12) =-13a(13) =14a(14) =15a(15) =16a(16) =-17a(17) =-18a(18) =-19a(19) =-20a(20) =21a(21) =22a(22) =-23a(23) =24a(24) =25a(25) =26a(26) =-27a(27) =-28a(28) =-29a(29) =-30