a(n) = sum of all divisors of all positive integers <= prime(n).

Terms

a(0) =4a(1) =8a(2) =21a(3) =41a(4) =99a(5) =141a(6) =238a(7) =297a(8) =431a(9) =690a(10) =794a(11) =1136a(12) =1384a(13) =1524a(14) =1806a(15) =2304a(16) =2846a(17) =3076a(18) =3699a(19) =4137a(20) =4406a(21) =5128a(22) =5645a(23) =6499a(24) =7755a(25) =8401a(26) =8721a(27) =9393a(28) =9783a(29) =10513