A134313 - OEIS

A134313

Numbers k such that k * Fibonacci(k) + 1 is prime.

1, 2, 3, 4, 9, 14, 15, 20, 24, 28, 30, 48, 54, 63, 108, 110, 116, 130, 148, 180, 189, 268, 315, 345, 394, 520, 528, 640, 808, 1070, 1112, 1590, 1744, 2530, 3630, 5640, 5778, 5938, 6795, 18160, 18858, 22444, 52160, 54621, 127700

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OFFSET

1,2

COMMENTS

Some of the larger entries may only correspond to probable primes.

LINKS

Table of n, a(n) for n=1..45.

MATHEMATICA

a={}; Do[f=Fibonacci[n]; p=n*f+1; If[PrimeQ[p], AppendTo[a, n]], {n, 1, 10^3}]; a (* Vladimir Joseph Stephan Orlovsky, Jul 22 2008 *)

Transpose[Select[Table[{n, Fibonacci[n]}, {n, 7000}], PrimeQ[Times@@#+1]&]] [[1]] (* Harvey P. Dale, Jul 28 2013 *)

PROG

(Magma) [n: n in [1..2000]| IsPrime(1+n*Fibonacci(n))]; // Vincenzo Librandi, Nov 02 2014

CROSSREFS

Sequence in context: A100902 A283447 A034793 * A307403 A220952 A188531

Adjacent sequences: A134310 A134311 A134312 * A134314 A134315 A134316

KEYWORD

more,nonn,changed

AUTHOR

Jason Earls, Jan 16 2008

EXTENSIONS

a(45) from Michael S. Branicky, Oct 26 2024

STATUS

approved