cp's OEIS Frontend

A285057 a(n) = lcm(n, A001177(n)).

%I A285057 #13 May 09 2021 11:18:56
%S A285057 1,6,12,12,5,12,56,24,36,30,110,12,91,168,60,48,153,36,342,60,168,330,
%T A285057 552,24,25,546,108,168,406,60,930,96,660,306,280,36,703,342,1092,120,
%U A285057 820,168,1892,660,180,552,752,48,392,150,612,1092,1431,108,110,168,684,1218,3422,60
%N A285057 a(n) = lcm(n, A001177(n)).
%H A285057 Indranil Ghosh, <a href="/A285057/b285057.txt">Table of n, a(n) for n = 1..5000</a>
%H A285057 Paolo Leonetti, Carlo Sanna, <a href="https://arxiv.org/abs/1704.00151">On the greatest common divisor of n and the nth Fibonacci number</a>, arXiv:1704.00151 [math.NT], 2017. See l(n) on page 2.
%F A285057 For p prime (except 5), a(p) = p*A001177(p). See Leonetti & Sanna link.
%t A285057 z[n_]:=Block[{k=1}, While[Mod[Fibonacci[k], n]!=0, k ++]; k]; a[n_]:=LCM[n, z[n]]; Table[a[n], {n, 100}] (* _Indranil Ghosh_, Apr 09 2017 *)
%o A285057 (PARI) z(n) = {my(k = 1); while (fibonacci(k) % n, k++); k;}
%o A285057 a(n) = lcm(n, z(n));
%o A285057 (Python)
%o A285057 from sympy import fibonacci, lcm
%o A285057 def z(n):
%o A285057     k=1
%o A285057     while fibonacci(k)%n: k+=1
%o A285057     return k
%o A285057 def a(n): return lcm(n, z(n))
%o A285057 print([a(n) for n in range(1,201)]) # _Indranil Ghosh_, Apr 09 2017
%Y A285057 Cf. A001177.
%K A285057 nonn
%O A285057 1,2
%A A285057 _Michel Marcus_, Apr 09 2017