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 A124067 #38 Jun 18 2023 01:49:30 %S A124067 1,2,3,4,5,6,8,11,13,19,21,22,24,27,40,44,51,62,92,139,208,224,293, %T A124067 307,421,509,741,861,966,989,1046,1100,1102,1109,1182,1547,1766,1813, %U A124067 2048,2720,2726,6012,6790,7132,8301,8699,10062,11102,15827,23918,26747,29389,37229,38211,68726 %N A124067 Numbers k such that 2*F(k) + 1 is a prime, where F = A000045. %t A124067 Select[Range[10000], PrimeQ[2 Fibonacci[#] + 1]&] (* _Vincenzo Librandi_, Aug 13 2013 *) %o A124067 (PARI) isok(n) = isprime(2*fibonacci(n)+1) \\ _Michel Marcus_, Jun 03 2013 %o A124067 (Magma) [n: n in [1..1200] | IsPrime(2*Fibonacci(n)+1)]; // _Vincenzo Librandi_, Aug 13 2013 %o A124067 (PARI) for(n=1,10^9,if(ispseudoprime(2*fibonacci(n)+1),print1(n,", "))); \\ _Joerg Arndt_, Aug 13 2013 %Y A124067 Cf. A000045, A001588, A124081 (associated primes). %K A124067 nonn %O A124067 1,2 %A A124067 _Giovanni Teofilatto_, Dec 12 2006 %E A124067 Inserted a(1)=1 and extended by _Michel Marcus_, Jun 03 2013 %E A124067 More terms from _Vincenzo Librandi_, Aug 13 2013 %E A124067 a(48) from _Jorge Coveiro_, Sep 05 2022 %E A124067 a(49)-a(55) from _Michael S. Branicky_, Jun 17 2023