Abstract
This article describes all discriminants D for which the length of the period of the expansion of √D in a continued fraction is equal to 2, 3, 4, or 6. It is proved that such discriminants are small. Similar propositions are proved for prime discriminants D=ρ.
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Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 185, pp. 13–21, 1990.
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Golubeva, E.P. Indefinite binary quadratic forms with large class numbers. J Math Sci 59, 1142–1148 (1992). https://doi.org/10.1007/BF01374075
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DOI: https://doi.org/10.1007/BF01374075