login
Number of primes <= 5^n.
0

%I #27 Oct 07 2015 15:56:40

%S 0,3,9,30,114,445,1821,7671,33118,145713,650133,2934858,13375865,

%T 61444585,284140656,1321453490,6175961983,28988040005,136575061279,

%U 645620925545,3061129684411,14552990145243,69354801708586,331251325552977,1585299642009257,7600886353341754,36504944044424979,175596829407110803,845879609035799508,4080206964520522386,19705939422430380037,95283357078617397618,461221032128956299315

%N Number of primes <= 5^n.

%H <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes in various ranges</a>

%F a(n) = A000720(A000351(n)). - _Michel Marcus_, Aug 25 2014

%t Table[PrimePi[5^n], {n, 0, 19}]

%o (PARI) a(n) = primepi(5^n); \\ _Michel Marcus_, Aug 25 2014

%Y Cf. A006880, A007053 and A040014.

%K nonn

%O 0,2

%A _Robert G. Wilson v_, Jun 09 2000

%E a(19) corrected by _Henri Lifchitz_, Nov 11 2012

%E a(20)-a(27) from _Henri Lifchitz_, Nov 11 2012

%E a(28)-a(32) from _Henri Lifchitz_, Aug 25 2014

%E Definition corrected by _Jean-Claude Arbaut_, Oct 07 2015