2,1

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

P. E. Wood, Jr., Switching Theory, McGraw-Hill, 1968, see p. 263.

Cf. A006845.

Sequence in context: A075178 A145618 A140355 this_sequence A028424 A037311 A031257

Adjacent sequences: A007038 A007039 A007040 this_sequence A007042 A007043 A007044

nonn

N. J. A. Sloane (njas(AT)research.att.com).