a(n) = Sum_{k=1..n} k*floor( prime(k)/k ).

Terms

a(0) =2a(1) =4a(2) =7a(3) =11a(4) =21a(5) =33a(6) =47a(7) =63a(8) =81a(9) =101a(10) =123a(11) =159a(12) =198a(13) =240a(14) =285a(15) =333a(16) =384a(17) =438a(18) =495a(19) =555a(20) =618a(21) =684a(22) =753a(23) =825a(24) =900a(25) =978a(26) =1059a(27) =1143a(28) =1230a(29) =1320