a(n) = phi(n) - pi(n).

Terms

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