4,1

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

M. Gardner, Fractal Music, Hypercards and More, Freeman, NY, 1991, p. 240.

Sequence in context: A113691 A057454 A121929 this_sequence A004923 A044184 A044565

Adjacent sequences: A007627 A007628 A007629 this_sequence A007631 A007632 A007633

nonn

N. J. A. Sloane (njas(AT)research.att.com), Mira Bernstein, Robert G. Wilson v (rgwv(AT)rgwv.com)