847255055010domain: NAppears in sequencesa(n) = (-1)^n + (-2)^n - (-3)^n.at n=25A083321a(n) = (-1)^n + (-2)^n + 3^n (-1, -2 and 3 are the roots of the equation x^3 = 7*x + 6).at n=25A135399Expansion of e.g.f (exp(x)-1)*(exp(2*x)-1).at n=25A362316