This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A263880 #13 Nov 04 2015 00:21:09 %S A263880 5,7,11,179,467, %T A263880 21195998530602981465199287343010006825031720870818843865120019360285948694390966280586508792391539752259819 %N A263880 Safe primes 2p + 1 such that p is a Fibonacci prime. %C A263880 Same as safe primes q whose Sophie Germain prime (2q - 1)/2 is a Fibonacci number. %C A263880 No other terms up to 2*Fibonacci(2904353) + 1, according to the list of indices of 49 Fibonacci (probable) primes in A001605. %C A263880 In that range, the only safe Fibonacci prime is 5. Are there larger ones? %C A263880 There are six primes 2p + 1 such that p is a Fibonacci prime, namely, a(1) through a(6). By contrast, in the same range there are only two primes 2p - 1 such that p is a Fibonacci prime, namely, 2p - 1 = 3 and 5, for p = 2 and 3. Is there some modular restriction to explain this bias in favor of 2p + 1 over 2p - 1 among Fibonacci primes p? %H A263880 Wikipedia, <a href="https://en.wikipedia.org/wiki/Fibonacci_prime">Fibonacci prime</a> %H A263880 Wikipedia, <a href="https://en.wikipedia.org/wiki/Safe_prime">Safe prime</a> %H A263880 Wikipedia, <a href="https://en.wikipedia.org/wiki/Sophie_Germain_prime">Sophie Germain prime</a> %F A263880 a(n) = 2*A155011(n) + 1. %e A263880 179 is in the sequence because it is prime and (179 - 1)/2 = 89 = Fibonacci(11), which is also prime. %t A263880 2 * Select[Fibonacci[Range[2000]], And @@ PrimeQ[{#, 2 # + 1}] &] + 1 %Y A263880 Cf. A000045, A005384, A005385, A005478, A155011. %K A263880 nonn %O A263880 1,1 %A A263880 _Jonathan Sondow_, Nov 02 2015