{ "id": "math/0610732", "version": "v1", "published": "2006-10-24T16:14:34.000Z", "updated": "2006-10-24T16:14:34.000Z", "title": "On squares in Lucas sequences", "authors": [ "A. Bremner", "N. Tzanakis" ], "comment": "11 pages. To appear in Journal of Number Theory", "categories": [ "math.NT" ], "abstract": "Let P and Q be non-zero integers. The Lucas sequence U_n(P,Q) is defined by U_0=0, U_1=1, U_n= P*U_{n-1}-Q*U_{n-2} for n >1. The question of when U_n(P,Q) can be a perfect square has generated interest in the literature. We show that for n=2,...,7, U_n is a square for infinitely many pairs (P,Q) with gcd(P,Q)=1; further, for n=8,...,12, the only non-degenerate sequences where gcd(P,Q)=1 and U_n(P,Q)=square, are given by U_8(1,-4)=21^2, U_8(4,-17)=620^2, and U_12(1,-1)=12^2.", "revisions": [ { "version": "v1", "updated": "2006-10-24T16:14:34.000Z" } ], "analyses": { "subjects": [ "11B37", "11D41", "11G05", "11G30" ], "keywords": [ "lucas sequence", "non-zero integers", "non-degenerate sequences", "perfect square" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math.....10732B" } } }