13404268800domain: NAppears in sequencesa(1) = 1, a(n+1) = a(n)/T(n+1), if T(n+1) divides a(n), else a(n+1) = a(n) *T(n+1), where T(n) = n*(n+1)/2 is a triangular number (A000217).at n=15A111465