A270821 Numbers n such that F(n) - n is a prime, where F(n) denotes the n-th Fibonacci number.
6, 8, 16, 26, 28, 76, 148, 159, 808, 848, 916, 1143, 4036, 4959, 43239, 73432, 98716, 144039, 146132
Offset: 1
Examples
fibonacci(6) - 6 = 8 - 6 = 2 that is a prime; fibonacci(8) - 8 = 21 - 8 = 13 that is a prime.
Programs
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Maple
with(combinat): P:=proc(q) local n; for n from 0 to q do if isprime(fibonacci(n)-n) then print(n); fi; od; end: P(10^5);
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Mathematica
Select[Range[150000],PrimeQ[Fibonacci[#]-#]&] (* Harvey P. Dale, May 03 2018 *)
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PARI
lista(nn) = {for(n=1, nn, if(ispseudoprime(fibonacci(n)-n), print1(n, ", ")));} \\ Altug Alkan, Mar 30 2016
Extensions
a(15)-a(19) from Giovanni Resta, Apr 14 2016