A117595 Numbers n such that F(2*n - 1) is prime, where F(m) is a Fibonacci number.

2, 3, 4, 6, 7, 9, 12, 15, 22, 24, 42, 66, 69, 180, 216, 217, 225, 255, 285, 286, 1486, 2362, 2694, 4656, 4839, 7216, 12781, 15379, 18000, 18756, 25417, 40920, 52456, 65011, 74046, 100554, 198690, 216891, 295021, 296845, 302356

Offset: 1

Author

Parthasarathy Nambi, Apr 05 2006

Keywords

• nonn

Comments

See A001605, which is the main entry for Fibonacci primes, for the latest information. - N. J. A. Sloane, Jul 09 2016

Or, A001519(n) is prime. - Zak Seidov, Jul 04 2016

Examples

			If n=69 then F(2*n - 1) is a prime with 29 digits.
		

Links

• C. Caldwell's FibonacciPrime pages.
• H. Dubner and W. Keller, New Fibonacci and Lucas Primes, Math. Comp. 68 (1999) 417-427.
• PRP Top Records, Search for: F(n)

Crossrefs

Cf. A000045, A001605 (Fibonacci(n) is prime), A001519.

Programs

Mathematica

Select[Range[2500], PrimeQ[Fibonacci[2# - 1]] &] (* Stefan Steinerberger, Apr 06 2006 *)

PARI

{ for(n=1,10000, if ( isprime( fibonacci(2*n-1) ), print1(n,","); ); ); } \\ R. J. Mathar, Apr 07 2006

Formula

2*a(n)-1 = A001605(n+1) for all odd A001605(n+1). - R. J. Mathar, Apr 07 2006

Extensions

More terms from Stefan Steinerberger, T. D. Noe and R. J. Mathar, Apr 07 2006