Imaginary part of (5+12i)^n.

Terms

a(0) =0a(1) =12a(2) =120a(3) =-828a(4) =-28560a(5) =-145668a(6) =3369960a(7) =58317492a(8) =13651680a(9) =-9719139348a(10) =-99498527400a(11) =647549275812