a(0)=-2, a(1)=3; thereafter a(n) = 2*a(n-1) + a(n-2).

Terms

a(0) =-2a(1) =3a(2) =4a(3) =11a(4) =26a(5) =63a(6) =152a(7) =367a(8) =886a(9) =2139a(10) =5164a(11) =12467a(12) =30098a(13) =72663a(14) =175424a(15) =423511a(16) =1022446a(17) =2468403a(18) =5959252a(19) =14386907a(20) =34733066a(21) =83853039a(22) =202439144a(23) =488731327a(24) =1179901798a(25) =2848534923a(26) =6876971644a(27) =16602478211a(28) =40081928066a(29) =96766334343