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Largest prime below prime(n)^2 (A001248).
8

%I #23 May 04 2020 11:30:21

%S 3,7,23,47,113,167,283,359,523,839,953,1367,1669,1847,2207,2803,3469,

%T 3719,4483,5039,5323,6229,6883,7919,9403,10193,10607,11447,11867,

%U 12763,16127,17159,18757,19319,22193,22787,24631,26561,27883,29927,32029

%N Largest prime below prime(n)^2 (A001248).

%C For n > 1, the n-1 first primes determine the primes up to a(n). This is how the Sieve of Eratosthenes works. - _Jean-Christophe Hervé_, Oct 21 2013

%H Robert Israel, <a href="/A054270/b054270.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = Max[prime q: q < prime(n)^2].

%F a(n) = prime(A000879(n)) = A000040(A000879(n)). - _Jean-Christophe Hervé_, Oct 21 2013

%p seq(prevprime(ithprime(i)^2),i=1..100); # _Robert Israel_, May 04 2020

%t NextPrime[Prime[Range[50]]^2,-1] (* _Harvey P. Dale_, May 19 2016 *)

%o (PARI) a(n) = precprime(prime(n)^2); \\ _Michel Marcus_, Dec 13 2013

%Y Cf. A001248, A054271.

%K nonn

%O 1,1

%A _Labos Elemer_, May 05 2000