cp's OEIS Frontend

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.

A057665 Numbers k such that prime(k) + 2^prime(k) is prime.

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%I A057665 #31 Sep 01 2024 10:28:43
%S A057665 2,3,24,66,126
%N A057665 Numbers k such that prime(k) + 2^prime(k) is prime.
%C A057665 a(6) > 3002, since prime(3002) = 27479 (see comment by _Ralf Stephan_ in A057663). - _Michel Marcus_, Dec 20 2013
%C A057665 These values correspond to indices ip = 2, 3, 9, 10, 11 where A052007(ip) is prime. - _Michel Marcus_, Dec 20 2013
%C A057665 If it exists, a(6) > 15*10^3. - _Michal Paulovic_, Sep 24 2023
%C A057665 If it exists, a(6) > 30*10^3. - _Michael S. Branicky_, Sep 01 2024
%F A057665 a(n) = primepi(A057663(n)). - _Michel Marcus_, Dec 20 2013
%t A057665 Select[Range[10^3], PrimeQ[# + 2^#] &@ Prime@ # &] (* _Michael De Vlieger_, Oct 26 2017 *)
%o A057665 (PARI) isok(n) = isprime(prime(n) + 2^prime(n)); \\ _Michel Marcus_, Dec 19 2013
%Y A057665 Cf. A052007, A057663, A057664.
%K A057665 nonn,more,hard
%O A057665 1,1
%A A057665 _Labos Elemer_, Oct 16 2000
%E A057665 Name edited by _Michel Marcus_, Dec 19 2013