a(0)=-5, a(1)=6; thereafter a(n) = 2*a(n-1) + a(n-2).

Terms

a(0) =-5a(1) =6a(2) =7a(3) =20a(4) =47a(5) =114a(6) =275a(7) =664a(8) =1603a(9) =3870a(10) =9343a(11) =22556a(12) =54455a(13) =131466a(14) =317387a(15) =766240a(16) =1849867a(17) =4465974a(18) =10781815a(19) =26029604a(20) =62841023a(21) =151711650a(22) =366264323a(23) =884240296a(24) =2134744915a(25) =5153730126a(26) =12442205167a(27) =30038140460a(28) =72518486087a(29) =175075112634