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Prime Fibonacci numbers with prime indices.
23

%I #20 Oct 13 2019 06:12:48

%S 2,5,13,89,233,1597,28657,514229,433494437,2971215073,

%T 99194853094755497,1066340417491710595814572169,

%U 19134702400093278081449423917,475420437734698220747368027166749382927701417016557193662268716376935476241

%N Prime Fibonacci numbers with prime indices.

%C Same as A005478 except that F(4) = 3 has been omitted.

%C Sequence of primes in A001519. [_James R. Buddenhagen_, May 20 2010]

%H T. D. Noe, <a href="/A075737/b075737.txt">Table of n, a(n) for n = 1..20</a>

%e 5 is a prime and fibonacci(5)=5 is also a prime, 7 is a prime and fibonacci(7)=13 is also a prime, but 2 is a prime and fibonacci(2)=1 is not a prime.

%p with(combinat, fibonacci): fib_supM_pra := proc(n); if (isprime(n)='true') then if (isprime(fibonacci(n))='true') then RETURN(fibonacci(n)); fi; fi; end: seq(fib_supM_pra(i), i=1..500);

%t Fibonacci[ Prime[ Select[ Range[50], PrimeQ[ Fibonacci[ Prime[ # ]]] & ]]]

%t Module[{nn=500,fibs},fibs=Fibonacci[Range[nn]];Select[Pick[fibs,Table[ If[ PrimeQ[n],1,0],{n,nn}],1],PrimeQ]] (* _Harvey P. Dale_, Sep 13 2018 *)

%o (PARI) forprime(p=2,1e3,if(isprime(t=fibonacci(p)), print1(t", "))) \\ _Charles R Greathouse IV_, Feb 03 2014

%Y Subsequence of A030426.

%Y Cf. A000045, A005478, A083668, A001519.

%K nonn

%O 1,1

%A _Jani Melik_, Oct 07 2002