a(n+3) = 6*a(n) - 5*a(n+2), a(0) = -1, a(1) = 1, a(2) = -5.

Terms

a(0) =-1a(1) =1a(2) =-5a(3) =19a(4) =-89a(5) =415a(6) =-1961a(7) =9271a(8) =-43865a(9) =207559a(10) =-982169a(11) =4647655a(12) =-21992921a(13) =104071591a(14) =-492472025a(15) =2330402599a(16) =-11027583449a(17) =52183085095a(18) =-246933009881