5086263021domain: NAppears in sequencesa(n) = (1 - (-5)^n)/6.at n=14A014986Linear 2nd order recurrence: a(n) = 4*a(n-1) + 5*a(n-2).at n=15A015531a(n) = (5*5^n + (-1)^n)/6.at n=14A083425Expansion of (1-4*x-x^2)/((1-x)*(1-4*x-5*x^2)).at n=15A100284