a(n) = n * sigma_2(n).

Terms

a(0) =1a(1) =10a(2) =30a(3) =84a(4) =130a(5) =300a(6) =350a(7) =680a(8) =819a(9) =1300a(10) =1342a(11) =2520a(12) =2210a(13) =3500a(14) =3900a(15) =5456a(16) =4930a(17) =8190a(18) =6878a(19) =10920a(20) =10500a(21) =13420a(22) =12190a(23) =20400a(24) =16275a(25) =22100a(26) =22140a(27) =29400a(28) =24418a(29) =39000