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A033269 Numbers n such that every genus of binary quadratic forms of discriminant -4n consists of a single class and the class number h(-4n) = 16. 4
840, 1320, 1365, 1848 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989, p. 60.

G. B. Mathews, Theory of Numbers, Chelsea, no date, p. 263.

LINKS

Table of n, a(n) for n=1..4.

PROG

(PARI) ok(n)={my(u=quadclassunit(-4*n).cyc); #u==4 && !select(t->t<>2, u)} \\ Andrew Howroyd, Jun 09 2018

CROSSREFS

A subsequence of A000926.

Cf. A033266, A033267, A033268.

Sequence in context: A102793 A144770 A068546 * A272595 A179670 A092002

Adjacent sequences:  A033266 A033267 A033268 * A033270 A033271 A033272

KEYWORD

nonn,fini,full

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 31 00:53 EDT 2020. Contains 334747 sequences. (Running on oeis4.)