a(n) = 12^n - n^11.

Terms

a(0) =1a(1) =11a(2) =-1904a(3) =-175419a(4) =-4173568a(5) =-48579293a(6) =-359811072a(7) =-1941494935a(8) =-8159952896a(9) =-26221279257a(10) =-38082635776a(11) =457696700077