A104888 Class number of binary quadratic forms with radicand A005117(n).

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

Offset

2,2

Comments

The fundamental discriminant D and the radicand m (which is squarefree) are related via D=m if m=1 (mod 4) and D=4*m if m=2,3 (mod 4).

References

Hua Loo Keng, Introduction to Number Theory, Springer-Verlag, 1982, pp. 465-472.

Links

Table of n, a(n) for n=2..61.

S. R. Finch, Class number theory

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

Jens Jonasson, Classes of integral binary quadratic forms, Master's thesis (2001), Appendix B.

Crossrefs

Cf. A003646, A087048.

Sequence in context: A057768 A317990 A106030 * A286885 A365618 A254885

Adjacent sequences: A104885 A104886 A104887 * A104889 A104890 A104891

Keyword

nonn

Author

Steven Finch, May 03 2005

Status

approved