257658domain: NAppears in sequencesBase 7 digits are, in order, the first n terms of the periodic sequence with initial period 2,1,2.at n=6A037572Number of (finite) line segments formed by drawing all least squares regression lines fitted to n points (j,y_j), 0 <= j < n, where each y_j is 0 or 1.at n=14A371438