A154894 Fibonacci numbers whose number of proper divisors is prime.

8, 21, 34, 55, 377, 610, 987, 4181, 10946, 17711, 46368, 75025, 121393, 1346269, 3524578, 5702887, 9227465, 24157817, 39088169, 63245986, 165580141, 701408733, 1134903170, 1836311903, 7778742049, 12586269025, 20365011074, 53316291173

Offset: 1

Author

Omar E. Pol, Jan 25 2009

Keywords

• nonn

Examples

			8 is member because the number of proper divisors of 8 is 3, a prime number.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..494

Crossrefs

Cf. A000045, A152744.

Programs

Mathematica

Fibonacci[Select[Range[60], PrimeQ[DivisorSigma[0, Fibonacci[ # ]] - 1] &]] (* Stefan Steinerberger, Jan 31 2009 *)

Extensions

More terms from Stefan Steinerberger, Jan 31 2009