Dirichlet inverse of sigma function (A000203).

Terms

a(0) =1a(1) =-3a(2) =-4a(3) =2a(4) =-6a(5) =12a(6) =-8a(7) =0a(8) =3a(9) =18a(10) =-12a(11) =-8a(12) =-14a(13) =24a(14) =24a(15) =0a(16) =-18a(17) =-9a(18) =-20a(19) =-12a(20) =32a(21) =36a(22) =-24a(23) =0a(24) =5a(25) =42a(26) =0a(27) =-16a(28) =-30a(29) =-72