0,1

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 106.

Table of n, a(n) for n=0..55.

Partial sums of A004020. Cf. A057656, A057961, A057962.

Sequence in context: A304483 A268177 A083769 * A247066 A084724 A283233

Adjacent sequences: A057653 A057654 A057655 * A057657 A057658 A057659

nonn

N. J. A. Sloane, Oct 15 2000

approved