4315343domain: NAppears in sequencesa(n) = 5*a(n-2) - 2*a(n-4), with initial terms 0,1,1,3.at n=22A005824a(n) = 5*a(n-1) - 2*a(n-2); a(0)=1, a(1)=5.at n=10A107839a(n) = 5*a(n-2) - 2*a(n-4), n >= 4.at n=20A109165Expansion of (1+2*x-x^3) / (1-5*x^2+2*x^4).at n=20A384611