Let the sum of the first n terms of the sequence {an} be Sn, and the points (n, Sn / N) (n belongs to n) are all on the graph of function y = 1 / 2x-1 / 2 Let the sum of the first n terms of the sequence {an} be Sn, and the points (n, Sn / N) (n belongs to n) are all on the image of the function y = 1 / 2x-1 / 2, (1) Find the general term formula of sequence {an};

Let the sum of the first n terms of the sequence {an} be Sn, and the points (n, Sn / N) (n belongs to n) are all on the graph of function y = 1 / 2x-1 / 2 Let the sum of the first n terms of the sequence {an} be Sn, and the points (n, Sn / N) (n belongs to n) are all on the image of the function y = 1 / 2x-1 / 2, (1) Find the general term formula of sequence {an};

Substituting point (n, Sn / N), Sn / N = (1 / 2) n-1 / 2, that is, Sn = (1 / 2) [n (n-1)] and S (n-1) / (n-1) = (1 / 2) (n-1) - 1 / 2, that is, s (n-1) = (1 / 2) [(n-1) (n-2)], subtracting, an = SN-S (n-1) = (1 / 2) [n (n-1) - (n-1) (n-2)] = n-1 (n ≥ 2). Under A1 = 0 verification, we can