a(n) = -3*a(n-1) + 5*a(n-2), n > 1; a(0)=1, a(1)=-5.

Terms

a(0) =1a(1) =-5a(2) =20a(3) =-85a(4) =355a(5) =-1490a(6) =6245a(7) =-26185a(8) =109780a(9) =-460265a(10) =1929695a(11) =-8090410a(12) =33919705a(13) =-142211165a(14) =596232020a(15) =-2499751885a(16) =10480415755a(17) =-43940006690a(18) =184222098845a(19) =-772366329985