a(n) = 3*a(n-2) - 4*a(n-4) with a(0) = 2, a(1) = 1, a(2) = 3, a(3) = 1.

Terms

a(0) =2a(1) =1a(2) =3a(3) =1a(4) =1a(5) =-1a(6) =-9a(7) =-7a(8) =-31a(9) =-17a(10) =-57a(11) =-23a(12) =-47a(13) =-1a(14) =87a(15) =89a(16) =449a(17) =271a(18) =999a(19) =457a(20) =1201a(21) =287a(22) =-393a(23) =-967a(24) =-5983a(25) =-4049a(26) =-16377a(27) =-8279a(28) =-25199a(29) =-8641