A003638 - OEIS

A003638

Number of classes per genus in quadratic field with discriminant -4n, -n == 2,3( mod 4).
(Formerly M0191)

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

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OFFSET

1,7

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..75.

CROSSREFS

Cf. A003637.

Sequence in context: A361025 A152805 A064894 * A094267 A136480 A050603

Adjacent sequences: A003635 A003636 A003637 * A003639 A003640 A003641

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mira Bernstein

STATUS

approved