The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A023173 Numbers k such that Fib(k) == 1 (mod k). 12
 1, 2, 11, 19, 22, 29, 31, 38, 41, 58, 59, 61, 62, 71, 79, 82, 89, 101, 109, 118, 122, 131, 139, 142, 149, 151, 158, 178, 179, 181, 191, 199, 202, 211, 218, 229, 239, 241, 251, 262, 269, 271, 278, 281, 298, 302, 311, 323, 331, 349, 358, 359, 362, 379, 382, 389, 398, 401 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Sequence contains 1, A064739(k) for all k>=0, 2*A064739(k) for k>1. - Benoit Cloitre, Apr 06 2002 LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 MATHEMATICA lst={}; Do[If[Mod[Fibonacci[n], n]==1, AppendTo[lst, n]], {n, 1, 7!}]; Take[Union[lst], 5! ] (* Vladimir Joseph Stephan Orlovsky, Apr 03 2009 *) Select[Range[500], Mod[Fibonacci[#]-1, #]==0&] (* Harvey P. Dale, Sep 22 2021 *) PROG (PARI) fibmod(n, m)=((Mod([1, 1; 1, 0], m))^n)[1, 2] is(n)=fibmod(n, n)==1 \\ Charles R Greathouse IV, Oct 06 2016 CROSSREFS Cf. A045468, A003631, A064739. Sequence in context: A074926 A066144 A102343 * A018443 A163058 A161504 Adjacent sequences:  A023170 A023171 A023172 * A023174 A023175 A023176 KEYWORD nonn,easy AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 27 12:51 EST 2021. Contains 349394 sequences. (Running on oeis4.)