# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a234851 Showing 1-1 of 1 %I A234851 #11 Feb 19 2021 14:36:34 %S A234851 1,2,3,5,7,13,17,21,23,25,31,41,43,49,61,71,77,83,89,103,105,109,121, %T A234851 129,133,139,151,161,173,181,183,185,189,199,211,213,223,231,235,241, %U A234851 243,247,265,271,273,277,279,281,285,293,301,303,307,311,317 %N A234851 Indices of primes in A014692, i.e., numbers k such that prime(k)-k+1 is prime. %C A234851 Sequence A234695 lists primes in this sequence. %H A234851 Robert Israel, Table of n, a(n) for n = 1..10000 %F A234851 a(n) = PrimePi(A234850(n)), PrimePi = A000720. %p A234851 select(k -> isprime(ithprime(k)-k+1), [$1..1000]); # _Robert Israel_, Feb 19 2021 %o A234851 (PARI) for(k=1,999,isprime(prime(k)-k+1)&&print1(k",")) %o A234851 (PARI) is_A234851(n)=isprime(prime(k)-k+1) %Y A234851 Cf. A000040, A000720, A014692, A234695, A234850, A234852. %K A234851 nonn %O A234851 1,2 %A A234851 _M. F. Hasler_, Dec 31 2013 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE