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

Terms

a(0) =1a(1) =2a(2) =-2a(3) =-10a(4) =-2a(5) =38a(6) =46a(7) =-106a(8) =-290a(9) =134a(10) =1294a(11) =758a(12) =-4418a(13) =-7450a(14) =10222a(15) =40022a(16) =-866a(17) =-160954a(18) =-157490a(19) =486326a(20) =1116286a(21) =-829018a(22) =-5294162a(23) =-1978090a(24) =19198558a(25) =27110918a(26) =-49683314a(27) =-158126986a(28) =40606270a(29) =673114214