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Number of biased numbers (A101550) less than 10^n.
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%I #23 Aug 31 2014 07:48:07

%S 2,43,537,5866,61466,630509,6410996,64836667,653704646,6578501544,

%T 66115091613,663868597795,6661437722643,66808391053328,

%U 669760217536267,6712237657325964,67251395887426191

%N Number of biased numbers (A101550) less than 10^n.

%H G. Everest, S. Stevens, D. Tamsett and T. Ward, <a href="http://arxiv.org/abs/math/0412079">Primes Generated by Recurrence Sequences</a>, arXiv:math/0412079 [math.NT], 2004-2006.

%F a(n) ~ 10^n*log(2) as n -> infinity.

%t Accumulate@Table[Length@Select[Range[10^(n - 1), 10^n - 1], FactorInteger[#][[-1, 1]] > 2*Sqrt[#] &], {n, 5}] (* or *)

%t lst = {}; s = -2; Do[Do[If[PrimeQ[i] || FactorInteger[i][[-1, 1]] > 2*Sqrt[i], s++], {i, 10^(n - 1), 10^n - 1}]; AppendTo[lst, s], {n, 5}]; lst

%Y Cf. A101550, A002162.

%K more,nonn

%O 1,1

%A _Arkadiusz Wesolowski_, Dec 11 2012

%E a(9)-a(11) from _Donovan Johnson_, Dec 12 2012

%E a(12)-a(17) from _Hiroaki Yamanouchi_, Aug 31 2014