a(n) = 12^n - n^7.

Terms

a(0) =1a(1) =11a(2) =16a(3) =-459a(4) =4352a(5) =170707a(6) =2706048a(7) =35008265a(8) =427884544a(9) =5154997383a(10) =61907364224a(11) =742988883517