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%I #11 Jul 29 2017 12:04:48
%S 27,1243,78624,5762206,455055611,37607950277,3204942065688,
%T 279238344248553,24739954309690412,2220819602783663480,
%U 201467286691248261495,18435599767366347775141,1699246750872593033005720,157589269275974838158399968,14692398897720447639079087666
%N Floor of the integral of x/log(x) for x=2 to 10^n.
%C This integral is an approximation to the sum of x/log(x) for x=2 to 10^n and closely approximates Pi(n^2) for x = 2 to n.
%H Alois P. Heinz, <a href="/A163568/b163568.txt">Table of n, a(n) for n = 1..200</a>
%t Table[Floor[NIntegrate[x/Log[x], {x, 2, 10^n}]], {n, 1, 10}] (* _G. C. Greubel_, Jul 28 2017 *)
%o (PARI) g(n)=intnum(x=2,10^n,x/log(x)); for(x=1,20,print1(floor(g(x))","))
%Y Cf. A163521.
%K nonn
%O 1,1
%A _Cino Hilliard_, Jul 30 2009
%E Edited (but not checked) by _N. J. A. Sloane_, Aug 01 2009
%E Offset and upper limit in the definition corrected by _R. J. Mathar_, Aug 02 2009
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