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The graph of the first differences (A138684) of this sequence is fractal-like.
Table of n, a(n) for n=1..66.
Cf. A001333, A005652, A114889, A138684.
Sequence in context: A065193 A116047 A061885 * A072426 A189137 A230548
Adjacent sequences: A138680 A138681 A138682 * A138684 A138685 A138686
John W. Layman, Mar 26 2008