656982441984domain: NAppears in sequencesa(n) = 2*a(n-1) + 4*a(n-2) - 4*a(n-3) - 4*a(n-4).at n=28A099176Expansion of (1-4*x)/(1-6*x-12*x^2+8*x^3).at n=14A108476