A175247 - OEIS

%I #14 Jan 26 2023 11:30:10

%S 2,3,5,11,17,31,41,59,67,83,109,127,157,179,191,211,241,277,283,331,

%T 353,367,401,431,461,509,547,563,587,599,617,709,739,773,797,859,877,

%U 919,967,991,1031,1063,1087,1153,1171,1201,1217,1297,1409,1433,1447

%N Primes (A000040) with noncomposite (A008578) subscripts.

%C A006450 is the main entry for these numbers. [_Arkadiusz Wesolowski_, Mar 12 2011]

%F a(n) U A007821(n+1) = A000040(n) for n >= 1. a(n) = prime(noncomposite(n)) = A000040(A008578(n)). a(1) = 2, a(n) = A006450(n-1) for n >= 2.

%e a(5) = 17 because a(5) = p(q(5)) = p(7) = 17, p = prime, q = noncomposite.

%Y Cf. A006450, A000040.

%K nonn

%O 1,1

%A _Jaroslav Krizek_, Mar 13 2010