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

Terms

a(0) =2a(1) =1a(2) =-3a(3) =-5a(4) =1a(5) =11a(6) =9a(7) =-13a(8) =-31a(9) =-5a(10) =57a(11) =67a(12) =-47a(13) =-181a(14) =-87a(15) =275a(16) =449a(17) =-101a(18) =-999a(19) =-797a(20) =1201a(21) =2795a(22) =393a(23) =-5197a(24) =-5983a(25) =4411a(26) =16377a(27) =7555a(28) =-25199a(29) =-40309