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 A227799 Number of composites removed in each step of the Sieve of Eratosthenes for 10^10. 3

%I

%S 4999999999,1666666666,666666666,380952380,207792207,159840159,

%T 112828348,95013343,74358271,56409724,50950713,41311372,36273411,

%U 33742734,30153115,26170720,23065826,21931483,19640105,18256894,17506397,15954848,14993294,13813524,12531256

%N Number of composites removed in each step of the Sieve of Eratosthenes for 10^10.

%C a(n) = the number of composites <= 10^10 for which the n-th prime is the least prime factor.

%C pi(sqrt(10^10)) = the number of terms of this sequence.

%C The sum of a(n) for n = 1..3401 = A000720(10^10) + A065855(10^10).

%H Eric F. O'Brien, <a href="/A227799/b227799.txt">Table of n, a(n) for n = 1..9592</a>

%e a(1) = 10^10 \ 2 - 1.

%e a(2) = 10^10 \ 3 - 10^10 \ (2*3) - 1.

%e a(3) = 10^10 \ 5 - 10^10 \ (2*5) - 10^10 \ (3*5) + 10^10 \ (2*3*5) - 1.

%e a(4) = 10^10 \ 7 - 10^10 \ (2*7) - 10^10 \ (3*7) - 10^10 \ (5*7) + 10^10 \ (2*3*7) + 10^10 \ (2*5*7) + 10^10 \ (3*5*7) - 10^10 \ (2*3*5*7) - 1.

%Y Cf. A133228, A145538, A145539, A145540, A145583, A227155, A227797, A227798, A145532, A145533, A145534, A145535, A145536, A145537.

%K nonn,fini

%O 1,1

%A _Eric F. O'Brien_, Jul 31 2013

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Last modified April 18 22:28 EDT 2021. Contains 343090 sequences. (Running on oeis4.)