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A051995 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 r. 0
9, 1, 3, 1, 1, 1, 19, 7, 23, 25, 5, 9, 1, 31, 1, 7, 7, 1, 3, 1, 13, 41, 43, 3, 15, 15, 9, 3, 7, 1, 49, 17, 1, 53, 11, 11, 19, 59, 3, 1, 13, 4, 1, 23, 5, 15, 7, 11, 27, 5, 5, 1, 3, 1, 7, 1, 19, 3, 101, 7, 3, 3, 11, 25, 127, 43, 7, 27, 13, 29, 3, 31, 3, 1, 25, 59, 179, 9, 7, 47 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

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..79.

CROSSREFS

Cf. A051990-A051998.

Sequence in context: A005482 A080504 A154490 * A198835 A010167 A154181

Adjacent sequences:  A051992 A051993 A051994 * A051996 A051997 A051998

KEYWORD

nonn,fini

AUTHOR

N. J. A. Sloane, Jan 04 2000

STATUS

approved

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Last modified May 19 20:41 EDT 2019. Contains 323410 sequences. (Running on oeis4.)