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.

105, 120, 165, 168, 210, 240, 273, 280, 312, 330, 345, 357, 385, 408, 462, 520, 760

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• fini
• full

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.

Crossrefs

A subsequence of A000926.

Cf. A033266, A033267, A033269.

Programs

PARI

ok(n)={my(u=quadclassunit(-4*n).cyc); #u==3 && !select(t->t<>2, u)} \\ Andrew Howroyd, Jun 09 2018