54566domain: NAppears in sequencesG.f.: A(x) = INV(x - x*INV(x - 2*x^2*INV(x - 3*x^3*INV(x - 4*x^4*INV(x - ...))))), where INV(F(x)) = series reversion of F(x).at n=9A196709Number of length n+4 0..5 arrays with every five consecutive terms having four times some element equal to the sum of the remaining four.at n=20A249653