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

Terms

a(0) =-1a(1) =1a(2) =-4a(3) =4a(4) =-13a(5) =16a(6) =-43a(7) =61a(8) =-145a(9) =226a(10) =-496a(11) =823a(12) =-1714a(13) =2965a(14) =-5965a(15) =10609a(16) =-20860a(17) =37792a(18) =-73189a(19) =134236a(20) =-257359a(21) =475897a(22) =-906313a(23) =1685050a(24) =-3194836a(25) =5961463a(26) =-11269558a(27) =21079225a(28) =-39770137a(29) =74507233