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A003651 Class number of real quadratic field with discriminant 4n, n == 2,3 ( mod 4).
(Formerly M0066)
1
1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 2, 2, 1, 1, 2, 1, 2, 1, 2, 2, 3, 4, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 1, 4, 1, 1, 2, 1, 3, 2, 2, 1, 2, 2, 1, 2, 1, 1, 1, 4, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 4, 1, 2, 2, 1, 4, 1, 1, 2, 2, 4, 2, 3, 8, 1, 2, 4, 6, 2, 1, 2, 2, 1, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,5

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=2..106.

CROSSREFS

Cf. A003650.

Sequence in context: A120675 A072699 A143589 * A325028 A073203 A073204

Adjacent sequences:  A003648 A003649 A003650 * A003652 A003653 A003654

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mira Bernstein

STATUS

approved

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Last modified February 28 08:28 EST 2020. Contains 332323 sequences. (Running on oeis4.)