69206436005domain: NAppears in sequencesa(n) = (6*7^n + (-7)^n)/7.at n=13A083224a(n) = 5*7^n.at n=12A193577Expansion of g.f. (1-2*x)/(1-7*x).at n=13A196661a(n) = 5*343^n.at n=4A324265