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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
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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 April 24 11:14 EDT 2024. Contains 371936 sequences. (Running on oeis4.)