a(n) = sigma(n) - 4*phi(n).

Terms

a(0) =-3a(1) =-1a(2) =-4a(3) =-1a(4) =-10a(5) =4a(6) =-16a(7) =-1a(8) =-11a(9) =2a(10) =-28a(11) =12a(12) =-34a(13) =0a(14) =-8a(15) =-1a(16) =-46a(17) =15a(18) =-52a(19) =10a(20) =-16a(21) =-4a(22) =-64a(23) =28a(24) =-49a(25) =-6a(26) =-32a(27) =8a(28) =-82a(29) =40