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On the largest prime factor of the $k-$Fibonacci numbers

Number Theory 2012-10-16 v1

Abstract

Let P(m)P(m) denote the largest prime factor of an integer m2m\geq 2, and put P(0)=P(1)=1P(0)=P(1)=1. For an integer k2k\geq 2, let (Fn(k))n2k(F_{n}^{(k)})_{n\geq 2-k} be the kk-generalized Fibonacci sequence which starts with 0,...,0,10,...,0,1 (kk terms) and each term afterwards is the sum of the kk preceding terms. Here, we show that if nk+2n\geq k+2, then P(Fn(k))>cloglognP(F_n^{(k)})>c\log\log n, where c>0c>0 is an effectively computable constant. Furthermore, we determine all the kk-Fibonacci numbers Fn(k)F_n^{(k)} whose largest prime factor is less than or equal to 7.

Keywords

Cite

@article{arxiv.1210.4101,
  title  = {On the largest prime factor of the $k-$Fibonacci numbers},
  author = {Jhon J. Bravo and Florian Luca},
  journal= {arXiv preprint arXiv:1210.4101},
  year   = {2012}
}

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15 pages