A094412 Numbers k that divide Fibonacci(k+1) but do not divide Fibonacci(k) + 1.

323, 377, 2834, 3827, 6479, 11663, 18407, 19043, 20999, 23407, 25877, 27323, 34943, 35207, 39203, 44099, 47519, 50183, 51983, 53663, 60377, 65471, 78089, 79547, 81719, 82983, 84279, 84419, 86063, 90287, 94667, 104663, 109871, 121103, 121393

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..1000

Mathematica

Select[Range[50000], ! Mod[Fibonacci[ # ] + 1, # ] == 0 && Mod[Fibonacci[ # + 1], # ] == 0 &]
Select[Range[122000], Divisible[{Fibonacci[#+1], Fibonacci[#]+1}, #]=={True, False}&] (* Harvey P. Dale, Apr 16 2019 *)

Prog

(PARI) fibmod(n, m)=(Mod([0, 1; 1, 1], m)^n*[0; 1])[1, 1]
is(n)=fibmod(n+1, n)==0 && fibmod(n, n)!=-1 \\ Charles R Greathouse IV, Nov 04 2016

Crossrefs

Cf. A000045, A069107, A094395, A094401, A094411.

Sequence in context: A217120 A081264 A069107 * A182504 A177745 A065822

Adjacent sequences: A094409 A094410 A094411 * A094413 A094414 A094415

Keyword

nonn

Author

Eric Rowland, May 01 2004

Status

approved