|
| |
|
|
A014599
|
|
Class numbers h(D) of imaginary quadratic fields with discriminant D=1-4*n.
|
|
3
|
|
|
|
1, 1, 1, 2, 1, 3, 1, 3, 2, 4, 1, 5, 2, 4, 3, 4, 1, 7, 2, 5, 3, 6, 2, 8, 2, 5, 3, 8, 2, 10, 2, 5, 5, 6, 3, 10, 2, 7, 4, 10, 1, 11, 4, 6, 5, 8, 2, 13, 4, 9, 4, 6, 3, 14, 4, 7, 5, 12, 2, 15, 3, 6, 7, 12, 4, 13, 2, 11, 4, 12, 3, 14, 4, 8, 8, 10, 3, 19, 4, 10, 4, 12, 3, 18, 6, 7, 5, 12, 4, 19
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,4
|
|
|
COMMENTS
|
Also class number, or number of equivalence classes of positive definite binary quadratic forms of discriminant -(4n-1). - N. J. A. Sloane, May 28 2014
|
|
|
REFERENCES
|
D. A. Buell, Binary Quadratic Forms. Springer-Verlag, NY, 1989, pages 19 and 224-230. - N. J. A. Sloane, May 28 2014 [Only the squarefree cases appear on pp. 224-230]
H. Cohen, Course in Computational Alg. No. Theory, Springer, 1993, pp. 514-5.
|
|
|
LINKS
|
|
|
|
PROG
|
(PARI) a(n) = qfbclassno(1-4*n)
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Eric Rains (rains(AT)caltech.edu)
|
|
|
STATUS
|
approved
|
| |
|
|
