a(n) = (-1)^(n-1) + Sum_{d|n, d>1} a(n/d)^d.

Terms

a(0) =1a(1) =0a(2) =2a(3) =0a(4) =2a(5) =4a(6) =2a(7) =0a(8) =10a(9) =4a(10) =2a(11) =32a(12) =2a(13) =4a(14) =42a(15) =0a(16) =2a(17) =228a(18) =2a(19) =32a(20) =138a(21) =4a(22) =2a(23) =1536a(24) =34a(25) =4a(26) =1514a(27) =32a(28) =2a(29) =3940