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A051998 Consider real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+4k, k odd; sequence gives values of k. 9
1, -15, -5, -17, -19, -21, 1, -3, 1, 1, 5, 3, -33, 1, -35, -5, 5, -39, -13, -41, 3, 1, 1, -15, -3, 3, 5, 15, -7, -51, 1, 3, -55, 1, -5, 5, -3, 1, -21, -65, 5, 13, -69, 3, -15, 5, -11, 7, 3, -17, 17, -89, 29, -91, 13, -95, -5, 33, 1, -15, 35, 39, 11, 5, 1, 3, 19, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Excludes discriminants appearing in A051990.

REFERENCES

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

LINKS

Table of n, a(n) for n=0..67.

CROSSREFS

Cf. A051990-A051998.

Sequence in context: A070601 A196187 A004480 * A131611 A166209 A040215

Adjacent sequences:  A051995 A051996 A051997 * A051999 A052000 A052001

KEYWORD

sign,fini

AUTHOR

N. J. A. Sloane, Jan 04 2000

STATUS

approved

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Last modified April 23 18:15 EDT 2019. Contains 322387 sequences. (Running on oeis4.)