140455domain: NAppears in sequencesa(n) = A027011(2n, n+4).at n=5A027015T(n, 2n-9), T given by A027960.at n=13A027971Generalized Markoff numbers: largest number a in a 5-tuple a >= b >= c >= d >= e satisfying the Markoff(5) equation a^2 + b^2 + c^2 + d^2 + e^2 = 4*a*b*c*d*e.at n=21A229241