a(n) = n^6 * Sum_{d^2|n} 1 / d^6.

Terms

a(0) =1a(1) =64a(2) =729a(3) =4160a(4) =15625a(5) =46656a(6) =117649a(7) =266240a(8) =532170a(9) =1000000a(10) =1771561a(11) =3032640a(12) =4826809a(13) =7529536a(14) =11390625a(15) =17043456a(16) =24137569a(17) =34058880a(18) =47045881a(19) =65000000a(20) =85766121a(21) =113379904a(22) =148035889a(23) =194088960a(24) =244156250a(25) =308915776a(26) =387951930a(27) =489419840a(28) =594823321a(29) =729000000