a(n) = n^9 * Product_{p|n, p prime} (1 + 1/p^9).

Terms

a(0) =1a(1) =513a(2) =19684a(3) =262656a(4) =1953126a(5) =10097892a(6) =40353608a(7) =134479872a(8) =387440172a(9) =1001953638a(10) =2357947692a(11) =5170120704a(12) =10604499374a(13) =20701400904a(14) =38445332184a(15) =68853694464a(16) =118587876498a(17) =198756808236a(18) =322687697780a(19) =513000262656a(20) =794320419872