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%I #18 Mar 01 2018 02:32:00
%S 499999999,166666666,66666666,38095237,20779220,15984016,11282834,
%T 9501331,7435826,5640969,5095068,4131143,3627360,3374293,3015292,
%U 2616982,2306411,2192860,1963654,1825278,1750219,1595163,1499127,1381337,1253379,1191536
%N Number of composites removed in each step of the Sieve of Eratosthenes for 10^9.
%C a(n) = the number of composites <= 10^9 for which the n-th prime is the least prime factor.
%C pi(sqrt(10^9)) = the number of terms of this sequence.
%C The sum of a(n) for n = 1..3401 = A000720(10^9) + A065855(10^9).
%H Eric F. O'Brien, <a href="/A227798/b227798.txt">Table of n, a(n) for n = 1..3401</a>
%e a(1) = 10^9 \ 2 - 1.
%e a(2) = 10^9 \ 3 - 10^9 \ (2*3) - 1
%e a(3) = 10^9 \ 5 - 10^9 \ (2*5) - 10^9 \ (3*5) + 10^9 \ (2*3*5) - 1
%e a(4) = 10^9 \ 7 - 10^9 \ (2*7) - 10^9 \ (3*7) - 10^9 \ (5*7) + 10^9 \ (2*3*7) + 10^9 \ (2*5*7) + 10^9 \ (3*5*7) - 10^9 \ (2*3*5*7) - 1.
%Y Cf. A133228, A145538-A145540, A227155, A227797, A227799, A145532-A145537.
%K nonn,fini,full
%O 1,1
%A _Eric F. O'Brien_, Jul 31 2013
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