2017/07/29 by Khaochim, Narissara, Pongsriiam, Prapanpong
#11B39 #FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.1707.09512
Let Fn and Ln be the nth Fibonacci and Lucas number, respectively. For each positive integer m, the order of appearance of m in the Fibonacci sequence, denoted by z(m), is the smallest positive integer k such that m divides Fk. Recently, D. Marques has obtained a formula for z(FnFn+1), z(FnFn+1Fn+2), and z(FnFn+1Fn+2Fn+3). In this paper, we extend Marques' result to the case z(FnFn+1⋯ Fn+k) for every 4≤ k ≤ 6. We also give a formula for z(LnLn+1⋯ Ln+k) when k = 5,6 which extends the recent result of Marques and Trojovský. Our method gives a general idea on how to obtain the formulas for z(FnFn+1⋯ Fn+k) and z(LnLn+1⋯ Ln+k) for every k≥ 1.