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A033268
Numbers n such that every genus of binary quadratic forms of discriminant -4n consists of a single class and the class number h(-4n) = 8.
4
105, 120, 165, 168, 210, 240, 273, 280, 312, 330, 345, 357, 385, 408, 462, 520, 760
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.
PROG
(PARI) ok(n)={my(u=quadclassunit(-4*n).cyc); #u==3 && !select(t->t<>2, u)} \\ Andrew Howroyd, Jun 09 2018
CROSSREFS
A subsequence of A000926.
Sequence in context: A039553 A135999 A162304 * A325903 A095643 A206265
KEYWORD
nonn,fini,full
STATUS
approved