a(n) = Sum of all numbers of divisors of all numbers < (n+1)^2.

Terms

a(0) =5a(1) =20a(2) =45a(3) =84a(4) =131a(5) =198a(6) =273a(7) =368a(8) =473a(9) =602a(10) =731a(11) =894a(12) =1061a(13) =1252a(14) =1457a(15) =1686a(16) =1917a(17) =2186a(18) =2453a(19) =2752a(20) =3065a(21) =3402a(22) =3743a(23) =4122a(24) =4509a(25) =4918a(26) =5345a(27) =5804a(28) =6249a(29) =6754