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A051997 Consider real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+2k, k odd; sequence gives values of k. 8
-1, 1, 1, 3, 1, -1, 1, -3, 1, -1, -5, 3, 1, -1, -3, 3, -5, 1, 5, -3, 3, 7, -1, -1, -3, -5, -1, 1, 5, 1, -7, -1, 7, 1, -5, 1, -1, 3, 5, 1, 3, -3, 13, 5, 3, 1, -15, -5, 3, -7, 7, -3, 3, 13, -3, -11, 3, -15, 1, -1, -21, -33, 15, 3, -3, -5, 5, -17, 7, 3, 5, 1, -5, 7, 3, -13 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Excludes discriminants appearing in A051990.

REFERENCES

R. A. Mollin, Quadratics, CRC Press, 1996, Appendix A, Table A4(2), column k.

LINKS

Table of n, a(n) for n=1..76.

CROSSREFS

Cf. A051990, A051991, A051992, A051993, A051994, A051995, A051996, A051998.

Sequence in context: A155828 A226203 A327791 * A155744 A086869 A348953

Adjacent sequences: A051994 A051995 A051996 * A051998 A051999 A052000

KEYWORD

sign,fini,full

AUTHOR

N. J. A. Sloane, Jan 04 2000

EXTENSIONS

Offset changed to 1 by Georg Fischer, Sep 21 2021

STATUS

approved

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Last modified January 29 09:51 EST 2023. Contains 359915 sequences. (Running on oeis4.)