Abundance d = sigma(N) - 2*N = A033880(N) of numbers N = A153501(n), i.e., N has d > 0 as divisor.

Terms

a(0) =4a(1) =3a(2) =2a(3) =12a(4) =10a(5) =8a(6) =4a(7) =2a(8) =120a(9) =7a(10) =56a(11) =78a(12) =8a(13) =2a(14) =2a(15) =672a(16) =32a(17) =16a(18) =4a(19) =2a(20) =532a(21) =152a(22) =136a(23) =8a(24) =68a(25) =31a(26) =992a(27) =128a(28) =8a(29) =64