0,3

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 157.

E. C. Pervin, personal communication.

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

Sequence in context: A136966 A043523 A066270 this_sequence A006916 A128871 A110726

Adjacent sequences: A006912 A006913 A006914 this_sequence A006916 A006917 A006918

nonn

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