A023174 Numbers k such that Fibonacci(k) == 2 (mod k).

1, 3, 6, 77, 93, 123, 143, 213, 237, 267, 453, 483, 573, 597, 627, 717, 723, 813, 843, 933, 1077, 1203, 1227, 1293, 1317, 1347, 1437, 1517, 1563, 1707, 1763, 1797, 1803, 1893, 1923, 2157, 2253, 2283, 2307, 2427, 2517, 2643, 2691, 2733, 2757, 2787, 2973, 3021

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000045.

Programs

Mathematica

Select[Range[3100],Mod[Fibonacci[#]-2,#]==0&] (* Harvey P. Dale, Sep 22 2021 *)

PARI

is(n)=((Mod([1,1;1,0],n))^n)[1,2]==2 \\ Charles R Greathouse IV, Oct 28 2014