a(n) = Sum_{k=1..n} k * tau(k)^2, where tau is A000005.

Terms

a(0) =1a(1) =9a(2) =21a(3) =57a(4) =77a(5) =173a(6) =201a(7) =329a(8) =410a(9) =570a(10) =614a(11) =1046a(12) =1098a(13) =1322a(14) =1562a(15) =1962a(16) =2030a(17) =2678a(18) =2754a(19) =3474a(20) =3810a(21) =4162a(22) =4254a(23) =5790a(24) =6015a(25) =6431a(26) =6863a(27) =7871a(28) =7987a(29) =9907