Dirichlet convolution of primes (with 1) with sigma(n).

Terms

a(0) =1a(1) =5a(2) =7a(3) =18a(4) =13a(5) =40a(6) =21a(7) =61a(8) =44a(9) =74a(10) =41a(11) =157a(12) =51a(13) =120a(14) =113a(15) =194a(16) =71a(17) =261a(18) =81a(19) =293a(20) =179a(21) =220a(22) =103a(23) =542a(24) =162a(25) =278a(26) =256a(27) =461a(28) =137a(29) =654