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

Terms

a(0) =1a(1) =-17a(2) =80a(3) =-240a(4) =624a(5) =-1360a(6) =2400a(7) =-3840a(8) =6480a(9) =-10608a(10) =14640a(11) =-19200a(12) =28560a(13) =-40800a(14) =49920a(15) =-61440a(16) =83520a(17) =-110160a(18) =130320a(19) =-149760a(20) =192000a(21) =-248880a(22) =279840a(23) =-307200a(24) =390000a(25) =-485520a(26) =524880a(27) =-576000a(28) =707280a(29) =-848640