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%I #20 Apr 27 2024 03:36:03
%S 0,4,73,830,8769,90406,921500,9335419,94238543,949152464,9544947487,
%T 95881945185,962392087980,9653934463159,96795058249196,
%U 970155429577329,9720761658966073,97376442842345765,975260045712259138,9765942332723655391,97779180397439081158
%N Number of composites < 10^n.
%C The number 1 is omitted from the count as it is neither prime nor composite
%H Amiram Eldar, <a href="/A092871/b092871.txt">Table of n, a(n) for n = 0..29</a> (calculated using the b-file at A006880)
%H Chris Caldwell, <a href="https://t5k.org/howmany.html#table">The Prime Pages, How many primes are there? Table 1. Values of pi(x)</a>.
%F For n>0, a(n) = A065894(n) - 1 = 10^n - 2 - A006880(n). - _Max Alekseyev_, Aug 15 2013
%e 10^3 = 1000. 1000-2 = 998. a(3) = 830 because the 830 composites+168 primes must total 998.
%t Table[10^i-PrimePi[10^i]-2,{i,14}] (* _Harvey P. Dale_, Oct 01 2011 *) (* Mathematica's implementation of PrimePi does not work for 10^15 or above *)
%Y Cf. A065894, A006880, A092801, A092802.
%K nonn
%O 0,2
%A _Enoch Haga_, Mar 08 2004
%E Edited by _Max Alekseyev_, Aug 15 2013
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