cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A069104 Numbers m such that m divides Fibonacci(m+1).

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%I A069104 #28 Feb 24 2025 19:34:46
%S A069104 1,2,3,7,13,17,23,37,43,47,53,67,73,83,97,103,107,113,127,137,157,163,
%T A069104 167,173,193,197,223,227,233,257,263,277,283,293,307,313,317,323,337,
%U A069104 347,353,367,373,377,383,397,433,443,457,463,467,487,503,523,547,557
%N A069104 Numbers m such that m divides Fibonacci(m+1).
%C A069104 Equals A003631 union A069107.
%C A069104 Let u(1)=u(2)=1 and (m+2)*u(m+2) = (m+1)*u(m+1) + m*u(m); then sequence gives values of k such that u(k) is an integer.
%H A069104 Reinhard Zumkeller, <a href="/A069104/b069104.txt">Table of n, a(n) for n = 1..1000</a>
%t A069104 Select[Range[6! ],IntegerQ[Fibonacci[ #+1]/# ]&] (* _Vladimir Joseph Stephan Orlovsky_, Apr 03 2009 *)
%t A069104 Select[Range[600],Mod[Fibonacci[#+1],#]==0&] (* _Harvey P. Dale_, Feb 24 2025 *)
%o A069104 (Haskell)
%o A069104 import Data.List (elemIndices)
%o A069104 a069104 n = a069104_list !! (n-1)
%o A069104 a069104_list =
%o A069104    map (+ 1) $ elemIndices 0 $ zipWith mod (drop 2 a000045_list) [1..]
%o A069104 -- _Reinhard Zumkeller_, Oct 13 2011
%o A069104 (PARI) is(n)=((Mod([1,1;1,0],n))^n)[1,1]==0 \\ _Charles R Greathouse IV_, Feb 03 2014
%Y A069104 Cf. A000045, A023172, A123976, A159051.
%K A069104 easy,nonn
%O A069104 1,2
%A A069104 _Benoit Cloitre_, Apr 06 2002