a(n) = Sum_{k=1..n-1} k*sigma(k)*sigma(n-k).

Terms

a(0) =0a(1) =1a(2) =9a(3) =34a(4) =95a(5) =210a(6) =406a(7) =740a(8) =1161a(9) =1920a(10) =2695a(11) =4116a(12) =5369a(13) =7868a(14) =9690a(15) =13640a(16) =16116a(17) =22419a(18) =25365a(19) =34160a(20) =38640a(21) =50622a(22) =55154a(23) =73320a(24) =77225a(25) =100100a(26) =107730a(27) =135576a(28) =141085a(29) =182340