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

Terms

a(0) =1a(1) =7a(2) =19a(3) =47a(4) =77a(5) =149a(6) =205a(7) =325a(8) =442a(9) =622a(10) =754a(11) =1090a(12) =1272a(13) =1608a(14) =1968a(15) =2464a(16) =2770a(17) =3472a(18) =3852a(19) =4692a(20) =5364a(21) =6156a(22) =6708a(23) =8148a(24) =8923a(25) =10015a(26) =11095a(27) =12663a(28) =13533a(29) =15693