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Number of primes less than 10n.
23

%I #22 Apr 03 2023 10:36:09

%S 4,8,10,12,15,17,19,22,24,25,29,30,31,34,35,37,39,41,42,46,46,47,50,

%T 52,53,55,57,59,61,62,63,66,66,68,70,72,73,75,77,78,80,81,82,85,87,88,

%U 91,92,93,95,97,97,99,99,101,102,104,106,107,109,111,114,114,115,118,120

%N Number of primes less than 10n.

%C For almost all n, that is for a set of density 1, a(n) = a(n-1), and in all cases a(n) <= a(n-1) + 4. - _Charles R Greathouse IV_, Aug 27 2014

%H Robert G. Wilson v, <a href="/A038801/b038801.txt">Table of n, a(n) for n = 1..10000</a>

%H Andrew R. Booker, <a href="https://t5k.org/nthprime/">The Nth Prime Page</a>

%H Thomas R. Nicely, <a href="https://faculty.lynchburg.edu/~nicely/index.html">Some Results of Computational Research in Prime Numbers</a> [See local copy in A007053]

%H Tomás Oliveira e Silva, <a href="http://sweet.ua.pt/tos/primes.html">Tables of values of pi(x) and of pi2(x)</a>

%t Table[ PrimePi[ n*10 ], {n, 1, 66}] (* _Robert G. Wilson v_ *)

%o (PARI) a(n)=primepi(10*n) \\ _Charles R Greathouse IV_, Aug 27 2014

%Y Cf. A028505, A038812, A038813, A038814, A038815, A038816, A038817, A038818, A038819, A038820, A038821, A080122, A080123, A080124, A080125, A080126, A080127, A080128, A080129.

%K nonn

%O 1,1

%A _Jeff Burch_

%E Edited and corrected by _Robert G. Wilson v_, Jan 29 2003