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A051996 Consider real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+k, k odd; sequence gives values of k. 0
1, -1, 1, 5, -1, 3, -7, 1, -3, -5, 5, -11, 1, -1, 1, 13, -1, 7, -15, -3, 5, -1, 1, 3, 1, -5, 21, -1, 1, 1, -13, -15, 3, 15, -31, 1, -1, 1, 17, -35, -7, 5, -1, 1, 19, -39, -3, -5, 5, 41, 3, 5, -23, 1, 1, -3, 17, 13, -1, -19, -29, 1, -3, 5, -31, 21, 33, -3, -7, 35, 3, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

R. A. Mollin, Quadratics, CRC Press, 1996, Appendix A, Table A4.

LINKS

Table of n, a(n) for n=0..71.

CROSSREFS

Cf. A051990-A051998.

Sequence in context: A053544 A174879 A094136 * A242303 A214803 A225984

Adjacent sequences:  A051993 A051994 A051995 * A051997 A051998 A051999

KEYWORD

sign,fini

AUTHOR

N. J. A. Sloane, Jan 04 2000

STATUS

approved

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Last modified May 25 19:29 EDT 2019. Contains 323576 sequences. (Running on oeis4.)