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: A043523 A066270 A006915 this_sequence A128871 A110726 A124666

Adjacent sequences: A006913 A006914 A006915 this_sequence A006917 A006918 A006919

nonn,more

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