Lucas sequences whose 8th term is a square

dc.creatorBremner, Andrew
dc.creatorTzanakis, Nikos
dc.date2004-08-26
dc.date2004-08-27
dc.date.accessioned2026-07-07T05:11:35Z
dc.date.available2026-07-07T05:11:35Z
dc.descriptionLet P and Q be non-zero integers. The Lucas sequence U_n(P,Q), n=0,1,2,... is defined by U_0=0, U_1=1, U_n= P U_{n-1}-Q U_{n-2} for n>1. For each positive integer n<8 we describe all Lucas sequences with (P,Q)=1 having the property that U_n(P,Q) is a perfect square. The arguments are elementary. The main part of the paper is devoted to finding all Lucas sequences such that U_8(P,Q) is a perfect square. This reduces to a number of problems of similar type, namely, finding all points on an elliptic curve defined over a quartic number field subject to a ``Q-rationality'' condition on the X-coordinate. This is achieved by p-adic computations (for a suitable prime p) using the formal group of the elliptic curve.
dc.description21 pages + appendix of 23 pages with computational information
dc.identifierhttps://arxiv.org/abs/math/0408371
dc.identifierhttp://arxiv.org/abs/math/0408371
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/72295
dc.subjectNumber Theory
dc.subject11B39 (primary); 11G05 ; 11D25 (secondary)
dc.titleLucas sequences whose 8th term is a square
dc.typetext

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