Verified answer

a_n = c_1*(2^n)*(n!)

a_n = (-3/2)*(2^n)*(n!)

a_1 = -3

a_2 = -12

a_3 = -72

a_4 = -576

a_5 = -5760

a2 = 2(2)(a1) = -12

a3 = 2(3)(a2)=...

a4= ...

a5=...