a(n) = Sum_{k=1..n} gcd(k, n)^3.

Terms

a(0) =1a(1) =9a(2) =29a(3) =74a(4) =129a(5) =261a(6) =349a(7) =596a(8) =789a(9) =1161a(10) =1341a(11) =2146a(12) =2209a(13) =3141a(14) =3741a(15) =4776a(16) =4929a(17) =7101a(18) =6877a(19) =9546a(20) =10121a(21) =12069a(22) =12189a(23) =17284a(24) =16145a(25) =19881a(26) =21321a(27) =25826a(28) =24417a(29) =33669