A003646 Class number of binary quadratic forms with fundamental discriminant A003658(n),n>=2. (Formerly M0077)

1, 1, 2, 1, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 4, 1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 4, 1, 1, 4, 2, 2, 2, 4, 1, 4, 2, 4, 1, 2, 4, 1, 2, 4, 4, 2, 1, 2, 1, 2, 2, 2, 1, 1, 2, 4, 4, 2, 2, 2, 4, 4, 3, 2, 1, 2, 2, 1, 2, 2, 2, 3, 4, 2, 2, 1, 4, 1, 4, 1, 2, 4, 1, 2, 2, 4, 2, 4, 1, 6, 1, 6, 4, 2, 2, 1, 2, 2, 4

Offset

2,3

References

D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 236, 241.

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

Links

Table of n, a(n) for n=2..106.

S. R. Finch, Class number theory

Steven R. Finch, Class number theory [Cached copy, with permission of the author]

Wolfdieter Lang, Table for a(n), n=2, ..., 92 (see Part 2).

Crossrefs

Cf. A087048, A079896.

Sequence in context: A102418 A317989 A106032 * A201503 A112758 A029437

Adjacent sequences: A003643 A003644 A003645 * A003647 A003648 A003649

Keyword

nonn

Author

N. J. A. Sloane, Mira Bernstein

Status

approved