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A014600 Class numbers h(D) of imaginary quadratic fields with discriminant D=0,1 mod 4, D<0. 5
1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 3, 2, 1, 1, 3, 2, 2, 2, 4, 2, 1, 3, 5, 2, 2, 2, 4, 4, 3, 2, 4, 2, 1, 4, 7, 2, 2, 3, 5, 4, 3, 4, 6, 2, 2, 3, 8, 4, 2, 2, 5, 6, 3, 3, 8, 2, 2, 6, 10, 4, 2, 3, 5, 4, 5, 4, 6, 4, 3, 6, 10, 4, 2, 2, 7, 6, 4, 4, 10, 4, 1, 8, 11, 4, 4, 3, 6, 6, 5, 4, 8, 4, 2, 5, 13, 4, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

REFERENCES

H. Cohen, Course in Computational Alg. No. Theory, Springer, 1993, pp. 514-5.

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 0..10000

S. R. Finch, Class number theory

Steven R. Finch, Class number theory [Cached copy, with permission of the author]

Rick L. Shepherd, Binary quadratic forms and genus theory, Master of Arts Thesis, University of North Carolina at Greensboro, 2013.

PROG

(PARI) a(n)=qfbclassno(n\2*-4-n%2-3) \\ Charles R Greathouse IV, Apr 25 2013

(PARI) a(n)=quadclassunit(n\2*-4-n%2-3).no \\ Charles R Greathouse IV, Apr 25 2013

CROSSREFS

Sequence in context: A285202 A004737 A255616 * A165475 A319420 A267134

Adjacent sequences:  A014597 A014598 A014599 * A014601 A014602 A014603

KEYWORD

nonn

AUTHOR

Eric Rains (rains(AT)caltech.edu)

STATUS

approved

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Last modified December 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)