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On a family of diophantine triples {k, A 2 k + 2A, (A + 1)2 k + 2 (A + 1)} with two parameters

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Abstract

Let A and k be positive integers. We study the Diophantine quadruples

$$ \{ k,A^2 k + 2A,(A + 1)^2 k + 2(A + 1),d\} $$

. We prove that if d is a positive integer such that the product of any two distinct elements of the set increased by 1 is a perfect square, then

$$ \begin{gathered} d = (4A^4 + 8A^3 + 4A^2 )k^3 + (16A^3 + 24A^2 + 8A)k^2 \hfill \\ + (20A^2 + 20A + 4)k + (8A + 4) \hfill \\ \end{gathered} $$

when 3 ≦ A ≦ 10. This extends a theorem obtained by Dujella [7] for A = 1, and also, a classical theorem of Baker and Davenport [2] for A = k = 1.

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Correspondence to B. He.

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The first author is supported by the Foundation of Key Laboratory of Numerical Simulation of Sichuan Province. The second author is partially supported by Purdue University North Central.

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He, B., Togbé, A. On a family of diophantine triples {k, A 2 k + 2A, (A + 1)2 k + 2 (A + 1)} with two parameters. Acta Math Hung 124, 99–113 (2009). https://doi.org/10.1007/s10474-009-8155-5

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  • DOI: https://doi.org/10.1007/s10474-009-8155-5

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