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

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

Author

N. J. A. Sloane, Mira Bernstein

Keywords

• nonn

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

• 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.