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

Terms

a(0) =1a(1) =10a(2) =29a(3) =81a(4) =121a(5) =302a(6) =321a(7) =630a(8) =801a(9) =1264a(10) =1177a(11) =2521a(12) =1961a(13) =3234a(14) =4013a(15) =5140a(16) =4267a(17) =8013a(18) =5921a(19) =10701a(20) =10685a(21) =12166a(22) =10321a(23) =20458a(24) =15552a(25) =19610a(26) =21469a(27) =28473a(28) =20671a(29) =40340