a(n) = n^4 * Sum_{d^2|n} 1 / d^4.

Terms

a(0) =1a(1) =16a(2) =81a(3) =272a(4) =625a(5) =1296a(6) =2401a(7) =4352a(8) =6642a(9) =10000a(10) =14641a(11) =22032a(12) =28561a(13) =38416a(14) =50625a(15) =69888a(16) =83521a(17) =106272a(18) =130321a(19) =170000a(20) =194481a(21) =234256a(22) =279841a(23) =352512a(24) =391250a(25) =456976a(26) =538002a(27) =653072a(28) =707281a(29) =810000