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A090819 Primes p such that the p-th Fibonacci number is nonprime. 21
2, 19, 31, 37, 41, 53, 59, 61, 67, 71, 73, 79, 89, 97, 101, 103, 107, 109, 113, 127, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Is it true that a(n) ~ n log n? - Charles R Greathouse IV, Aug 15 2015
LINKS
EXAMPLE
Fibonacci(37) = 24157817 = 73*149*2221. [corrected by Bobby Jacobs, Sep 25 2017]
MATHEMATICA
Select[Prime[Range[62]], ! PrimeQ[Fibonacci[#]] &] (* Jayanta Basu, Jul 10 2013 *)
PROG
(PARI) f(n) = forprime(x=2, n, p=fibonacci(x); if(!isprime(p), print1(x", ")))
CROSSREFS
Essentially the same as A038672.
Sequence in context: A120276 A006962 A261312 * A254897 A059697 A103058
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Feb 11 2004
EXTENSIONS
Definition corrected by Don Reble, Sep 04 2008
STATUS
approved

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Last modified April 22 09:42 EDT 2024. Contains 371894 sequences. (Running on oeis4.)