<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0034-7426</journal-id>
<journal-title><![CDATA[Revista Colombiana de Matemáticas]]></journal-title>
<abbrev-journal-title><![CDATA[Rev.colomb.mat.]]></abbrev-journal-title>
<issn>0034-7426</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional de Colombia y Sociedad Colombiana de Matemáticas]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-74262012000100005</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Powers of Two in Generalized Fibonacci Sequences]]></article-title>
<article-title xml:lang="es"><![CDATA[Potencias de dos en sucesiones generalizadas de Fibonacci]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[BRAVO]]></surname>
<given-names><![CDATA[JHON J.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[LUCA]]></surname>
<given-names><![CDATA[FLORIAN]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad del Cauca  ]]></institution>
<addr-line><![CDATA[Popayán ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad Nacional Autónoma de México  ]]></institution>
<addr-line><![CDATA[Morelia ]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>15</day>
<month>06</month>
<year>2012</year>
</pub-date>
<pub-date pub-type="epub">
<day>15</day>
<month>06</month>
<year>2012</year>
</pub-date>
<volume>46</volume>
<numero>1</numero>
<fpage>67</fpage>
<lpage>79</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0034-74262012000100005&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0034-74262012000100005&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0034-74262012000100005&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[The k-generalized Fibonacci sequence \big(Fn(k)\big)n resembles the Fibonacci sequence in that it starts with 0,&hellip;,0,1 (k terms) and each term afterwards is the sum of the k preceding terms. In this paper, we are interested in finding powers of two that appear in k-generalized Fibonacci sequences; i.e., we study the Diophantine equation Fn(k)=2m in positive integers n,k,m with k&ge; 2.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[La sucesión k-generalizada de Fibonacci \big(Fn(k)\big)n se asemeja a la sucesión de Fibonacci, pues comienza con 0,&hellip;,0,1 (k términos) y a partir de ahí, cada término de la sucesión es la suma de los k precedentes. El interés en este artículo es encontrar potencias de dos que aparecen en sucesiones k-generalizadas de Fibonacci; es decir, se estudia la ecuación Diofántica Fn(k)=2m en enteros positivos n,k,m con k&ge; 2.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Fibonacci numbers]]></kwd>
<kwd lng="en"><![CDATA[Lower bounds for nonzero linear forms in logarithms of algebraic numbers]]></kwd>
<kwd lng="es"><![CDATA[Números de Fibonacci]]></kwd>
<kwd lng="es"><![CDATA[cotas inferiores para formas lineales en logaritmos de números algebraicos]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  <font size="2" face="verdana">      <p> <b> <font size="4">     <center> Powers of Two in Generalized Fibonacci Sequences </center> </font> </b> </p>      <p> <b> <font size="3">     <center> Potencias de dos en sucesiones generalizadas de Fibonacci </center> </font> </b> </p>      <p>     <center> JHON J. BRAVO<sup>1</sup>,  FLORIAN LUCA<sup>2</sup> </center> </p>      <p> <sup>1</sup>Universidad del Cauca, Popay&aacute;n, Colombia. Email: <a href="mailto:jbravo@unicauca.edu.co">jbravo@unicauca.edu.co</a>     <br>  <sup>2</sup>Universidad Nacional Aut&oacute;noma de M&eacute;xico, Morelia, M&eacute;xico. Email: <a href="mailto:fluca@matmor.unam.mx">fluca@matmor.unam.mx</a>     <br> </p>  <hr size="1">      ]]></body>
<body><![CDATA[<p> <b>     <center> Abstract </center> </b> </p>      <p> The <i>k-</i>generalized Fibonacci sequence <i>\big(F<sub>n</sub><sup>(k)</sup>\big)<sub>n</sub></i> resembles the Fibonacci sequence in that it starts with <i>0,&hellip;,0,1</i> (<i>k</i> terms) and each term afterwards is the sum of the <i>k</i> preceding terms. In this paper, we are interested in finding powers of two that appear in <i>k-</i>generalized Fibonacci sequences; i.e., we study the Diophantine equation <i>F<sub>n</sub><sup>(k)</sup>=2<sup>m</sup></i> in positive integers <i>n,k,m</i> with <i>k&ge; 2</i>. </p>      <p> <b> Key words: </b> Fibonacci numbers, Lower bounds for nonzero linear forms in logarithms of algebraic numbers. </p>  <hr size="1">  <i>2000 Mathematics Subject Classification: 11B39, 11J86.</i>  <hr size="1">      <p> <b>     <center> Resumen </center> </b> </p>      <p> La sucesi&oacute;n <i>k-</i>generalizada de Fibonacci <i>\big(F<sub>n</sub><sup>(k)</sup>\big)<sub>n</sub></i> se asemeja a la sucesi&oacute;n de Fibonacci, pues comienza con <i>0,&hellip;,0,1</i> (<i>k</i> t&eacute;rminos) y a partir de ah&iacute;, cada t&eacute;rmino de la sucesi&oacute;n es la suma de los <i>k</i> precedentes. El inter&eacute;s en este art&iacute;culo es encontrar potencias de dos que aparecen en sucesiones <i>k-</i>generalizadas de Fibonacci; es decir, se estudia la ecuaci&oacute;n Diof&aacute;ntica <i>F<sub>n</sub><sup>(k)</sup>=2<sup>m</sup></i> en enteros positivos <i>n,k,m</i> con <i>k&ge; 2</i>. </p>      <p> <b> Palabras clave: </b> N&uacute;meros de Fibonacci, cotas inferiores para formas lineales en logaritmos de n&uacute;meros algebraicos. </p>  <hr size="1">      <p> Texto completo disponible en <a href="pdf/rcm/v46n1/v46n1a05.pdf">PDF</a> </p>  <hr size="1">      <p> <b> <font size="3"> References </font> </b> </p>       ]]></body>
<body><![CDATA[<!-- ref --><p> &#91;1&#93; J. J. Bravo and F. Luca, '<i>k-</i>Generalized Fibonacci Numbers with only one Distinct Digit', <i>Preprint</i>,  (2011).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000023&pid=S0034-7426201200010000500001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> &#91;2&#93; Y. Bugeaud, M. Mignotte, and S. Siksek, 'Classical and Modular Approaches to Exponential Diophantine Equations. I. Fibonacci and Lucas Perfect Powers', <i>Ann. of Math.</i> <i>163</i>, 3 (2006), 969-1018.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000025&pid=S0034-7426201200010000500002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> &#91;3&#93; R. D. Carmichael, 'On the Numerical Factors of the Arithmetic Forms <i>&alpha;<sup>n</sup>\pm  &beta;<sup>n</sup></i>', <i>The Annals of Mathematics</i> <i>15</i>, 1/4 (1913), 30-70.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000027&pid=S0034-7426201200010000500003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> &#91;4&#93; G. P. Dresden, 'A Simplified Binet Formula for <i>k-</i>Generalized Fibonacci Numbers', <i>Preprint, arXiv:0905.0304v1</i>,  (2009).    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000029&pid=S0034-7426201200010000500004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> &#91;5&#93; A. Dujella and A. Peth&ouml;, 'A Generalization of a Theorem of Baker and Davenport', <i>Quart. J. Math. Oxford</i> <i>49</i>, 3 (1998), 291-306.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000031&pid=S0034-7426201200010000500005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      ]]></body>
<body><![CDATA[<!-- ref --><p> &#91;6&#93; E. M. Matveev, 'An Explicit Lower Bound for a Homogeneous Rational Linear Form in the Logarithms of Algebraic Numbers', <i>Izv. Math.</i> <i>64</i>, 6 (2000), 1217-1269.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000033&pid=S0034-7426201200010000500006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>      <!-- ref --><p> &#91;7&#93; D. A. Wolfram, 'Solving Generalized Fibonacci Recurrences', <i>The Fibonacci Quarterly</i> <i>36</i>, 2 (1998), 129-145.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000035&pid=S0034-7426201200010000500007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --> </p>  <hr size="1">      <center> <b>(Recibido en noviembre de 2011. Aceptado en marzo de 2012)</b> </center> <hr size="1">      <p> Este art&iacute;culo se puede citar en <i>LaTeX</i> utilizando la siguiente referencia bibliogr&aacute;fica de <i>BibTeX</i>: </p> <code><font size="2" face="verdana"> @ARTICLE{RCMv46n1a05,    <br>   AUTHOR = {Bravo, Jhon J. and Luca, Florian},    <br>   TITLE  = {{Powers of Two in Generalized Fibonacci Sequences}},    <br>   JOURNAL = {Revista Colombiana de Matem&aacute;ticas},    <br>  YEAR  = {2012},    ]]></body>
<body><![CDATA[<br>  volume = {46},    <br>  number = {1},    <br>  pages  = {67--79}    <br> } </font></code>  <hr size="1"> </font>      ]]></body><back>
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</article>
