A note on the number of solutions of the generalized Ramanujan-Nagell equation x 2 - D = p n

Yuan-e Zhao; Tingting Wang

Czechoslovak Mathematical Journal (2012)

  • Volume: 62, Issue: 2, page 381-389
  • ISSN: 0011-4642

Abstract

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Let D be a positive integer, and let p be an odd prime with p D . In this paper we use a result on the rational approximation of quadratic irrationals due to M. Bauer, M. A. Bennett: Applications of the hypergeometric method to the generalized Ramanujan-Nagell equation. Ramanujan J. 6 (2002), 209–270, give a better upper bound for N ( D , p ) , and also prove that if the equation U 2 - D V 2 = - 1 has integer solutions ( U , V ) , the least solution ( u 1 , v 1 ) of the equation u 2 - p v 2 = 1 satisfies p v 1 , and D > C ( p ) , where C ( p ) is an effectively computable constant only depending on p , then the equation x 2 - D = p n has at most two positive integer solutions ( x , n ) . In particular, we have C ( 3 ) = 10 7 .

How to cite

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Zhao, Yuan-e, and Wang, Tingting. "A note on the number of solutions of the generalized Ramanujan-Nagell equation $x^2-D=p^n$." Czechoslovak Mathematical Journal 62.2 (2012): 381-389. <http://eudml.org/doc/246966>.

@article{Zhao2012,
abstract = {Let $D$ be a positive integer, and let $p$ be an odd prime with $p\nmid D$. In this paper we use a result on the rational approximation of quadratic irrationals due to M. Bauer, M. A. Bennett: Applications of the hypergeometric method to the generalized Ramanujan-Nagell equation. Ramanujan J. 6 (2002), 209–270, give a better upper bound for $N(D, p)$, and also prove that if the equation $U^2-DV^2=-1$ has integer solutions $(U, V)$, the least solution $(u_1, v_1)$ of the equation $u^2-pv^2=1$ satisfies $p\nmid v_1$, and $D>C(p)$, where $C(p)$ is an effectively computable constant only depending on $p$, then the equation $x^2-D=p^n$ has at most two positive integer solutions $(x, n)$. In particular, we have $C(3)=10^7$.},
author = {Zhao, Yuan-e, Wang, Tingting},
journal = {Czechoslovak Mathematical Journal},
keywords = {generalized Ramanujan-Nagell equation; number of solution; upper bound; generalized Ramanujan-Nagell equation; number of solutions; upper bound},
language = {eng},
number = {2},
pages = {381-389},
publisher = {Institute of Mathematics, Academy of Sciences of the Czech Republic},
title = {A note on the number of solutions of the generalized Ramanujan-Nagell equation $x^2-D=p^n$},
url = {http://eudml.org/doc/246966},
volume = {62},
year = {2012},
}

TY - JOUR
AU - Zhao, Yuan-e
AU - Wang, Tingting
TI - A note on the number of solutions of the generalized Ramanujan-Nagell equation $x^2-D=p^n$
JO - Czechoslovak Mathematical Journal
PY - 2012
PB - Institute of Mathematics, Academy of Sciences of the Czech Republic
VL - 62
IS - 2
SP - 381
EP - 389
AB - Let $D$ be a positive integer, and let $p$ be an odd prime with $p\nmid D$. In this paper we use a result on the rational approximation of quadratic irrationals due to M. Bauer, M. A. Bennett: Applications of the hypergeometric method to the generalized Ramanujan-Nagell equation. Ramanujan J. 6 (2002), 209–270, give a better upper bound for $N(D, p)$, and also prove that if the equation $U^2-DV^2=-1$ has integer solutions $(U, V)$, the least solution $(u_1, v_1)$ of the equation $u^2-pv^2=1$ satisfies $p\nmid v_1$, and $D>C(p)$, where $C(p)$ is an effectively computable constant only depending on $p$, then the equation $x^2-D=p^n$ has at most two positive integer solutions $(x, n)$. In particular, we have $C(3)=10^7$.
LA - eng
KW - generalized Ramanujan-Nagell equation; number of solution; upper bound; generalized Ramanujan-Nagell equation; number of solutions; upper bound
UR - http://eudml.org/doc/246966
ER -

References

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  1. Bauer, M., Bennett, M. A., 10.1023/A:1015779301077, Ramanujan J. 6 (2002), 209-270. (2002) Zbl1010.11020MR1908198DOI10.1023/A:1015779301077
  2. Beukers, F., 10.4064/aa-39-2-113-123, Acta Arith. 39 (1981), 113-123. (1981) Zbl0377.10012MR0639621DOI10.4064/aa-39-2-113-123
  3. Le, M. H., 10.4064/aa-58-3-289-298, Acta Arith. 58 (1991), 289-298. (1991) MR1121088DOI10.4064/aa-58-3-289-298
  4. Le, M. H., On the number of solutions of the generalized Ramanujan-Nagell equation x 2 - D = p n , Publ. Math. Debrecen. 45 (1994), 239-254. (1994) MR1315938
  5. Le, M. H., 10.4064/aa-68-2-141-144, Acta Arith. 68 (1994), 141-144. (1994) Zbl0816.11055MR1305196DOI10.4064/aa-68-2-141-144
  6. Mordell, L. J., Diophantine Equations, London, Academic Press. (1969). (1969) Zbl0188.34503MR0249355
  7. Siegel, C. L., 10.1007/BF01211608, Diss. Göttingen, Math. Zeitschr. 10 (1921), 173-213 German. (1921) MR1544471DOI10.1007/BF01211608

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