A003639 - OEIS

A003639

Number of classes per genus in Q(sqrt -n), n squarefree.
(Formerly M0085)

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 3, 3, 3, 1, 3, 1, 2, 1, 1, 3, 2, 4, 1, 1, 2, 5, 1, 3, 2, 1, 1, 3, 3, 4, 2, 2, 1, 2, 1, 7, 2, 5, 2, 1, 5, 2, 3, 1, 5, 3, 6, 1, 1, 4, 4, 2, 7, 1, 5, 1, 3, 3, 3, 3, 4, 4, 2, 1, 3, 5, 5, 1, 5, 3, 1, 5, 1, 7, 4, 2, 3, 2, 2, 5, 2, 8, 7, 7, 2, 2, 3, 4, 5, 4, 1, 1, 5, 11, 3

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,10

REFERENCES

D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pp. 224-241.

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=1..104.

CROSSREFS

Sequence in context: A091318 A385603 A198898 * A174110 A264969 A320301

Adjacent sequences: A003636 A003637 A003638 * A003640 A003641 A003642

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mira Bernstein

STATUS

approved