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A228592 a(n) is the smallest number such that if x >= a(n), then pi^*(x) - pi^*(x/2) >= n, where pi^*(x) is the number of prime powers p^k <= x (k >= 1).

%I A228592 #8 Sep 03 2013 06:03:46
%S A228592 2,3,7,11,23,27,29,41,59,67,71,79,101,107,109,125,127,149,167,169,179,
%T A228592 181,227,229,233,239,263,269,281,283,307,311,347,349,359,367,373,401,
%U A228592 409,419,431,433,439,487,491,503,521,569,587,593,599,601,607,617,641
%N A228592 a(n) is the smallest number such that if x >= a(n), then pi^*(x) - pi^*(x/2) >= n, where pi^*(x) is the number of prime powers p^k <= x (k >= 1).
%C A228592 It is a subsequence of A000961.
%H A228592 Peter J. C. Moses, <a href="/A228592/b228592.txt">Table of n, a(n) for n = 1..10000</a>
%F A228592 a(n) <= A228520(n); a(n) ~ A000040(2*n), when n goes to the infinity.
%Y A228592 Cf. A000961, A104272, A228520.
%K A228592 nonn
%O A228592 1,1
%A A228592 _Vladimir Shevelev_, Aug 27 2013
%E A228592 More terms from _Peter J. C. Moses_, Aug 27 2013