|
%I #27 Nov 23 2023 09:12:02
%S 2,3,24,66,126
%N Numbers k such that prime(k) + 2^prime(k) is prime.
%C a(6) > 3002, since prime(3002) = 27479 (see comment by _Ralf Stephan_ in A057663). - _Michel Marcus_, Dec 20 2013
%C These values correspond to indices ip = 2, 3, 9, 10, 11 where A052007(ip) is prime. - _Michel Marcus_, Dec 20 2013
%C If it exists, a(6) > 15*10^3. - _Michal Paulovic_, Sep 24 2023
%F a(n) = primepi(A057663(n)). - _Michel Marcus_, Dec 20 2013
%t Select[Range[10^3], PrimeQ[# + 2^#] &@ Prime@ # &] (* _Michael De Vlieger_, Oct 26 2017 *)
%o (PARI) isok(n) = isprime(prime(n) + 2^prime(n)); \\ _Michel Marcus_, Dec 19 2013
%Y Cf. A052007, A057663, A057664.
%K nonn,more,hard
%O 1,1
%A _Labos Elemer_, Oct 16 2000
%E Name edited by _Michel Marcus_, Dec 19 2013
|
