A051993 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 r.

3, 4, 5, 1, 6, 2, 1, 8, 3, 2, 2, 1, 11, 12, 13, 1, 14, 2, 1, 5, 3, 16, 17, 6, 19, 4, 1, 22, 22, 23, 2, 2, 10, 2, 1, 31, 34, 34, 2, 1, 5, 7, 36, 37, 2, 1, 13, 8, 8, 1, 14, 9, 2, 46, 47, 16, 3, 4, 56, 3, 2, 58, 20, 12, 2, 3, 2, 23, 10, 2, 24, 73, 5, 4, 2, 16, 2, 4, 8, 8, 19, 98, 20, 2, 2, 4, 24, 11, 122, 4, 4, 142, 26, 68, 242, 278, 22, 32

Offset: 1

Author

N. J. A. Sloane, Jan 04 2000

Keywords

• nonn
• fini
• full

References

• R. A. Mollin, Quadratics, CRC Press, 1996, Appendix A, Table A4(1), column r.

Crossrefs

Cf. A051990, A051991, A051992, A051994, A051995, A051996, A051997, A051998.

Extensions

a(83) and following from Georg Fischer, Sep 21 2021