Abundance of n, or (sum of divisors of n) - 2n.

Terms

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