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A047784 Nearest integer to Li(n). 5

%I

%S 1,2,3,4,4,5,5,6,6,7,7,7,8,8,9,9,9,10,10,10,11,11,11,12,12,12,12,13,

%T 13,13,14,14,14,14,15,15,15,16,16,16,16,17,17,17,17,18,18,18,18,19,19,

%U 19,19,20,20,20,20,21,21,21,21,22,22,22,22,23,23,23,23

%N Nearest integer to Li(n).

%D M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 238.

%H G. C. Greubel, <a href="/A047784/b047784.txt">Table of n, a(n) for n = 2..10000</a>

%H M. Abramowitz and I. A. Stegun, eds., <a href="http://www.convertit.com/Go/ConvertIt/Reference/AMS55.ASP">Handbook of Mathematical Functions</a>, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

%F a(n) = round(logarithmic integral(n)). - _G. C. Greubel_, May 16 2019

%t Table[Round[LogIntegral[n]], {n, 2, 80}] (* _G. C. Greubel_, May 16 2019 *)

%o (PARI) vector(80, n, n++; round(real(-eint1(-log(n)))) ) \\ _G. C. Greubel_, May 16 2019

%o (MAGMA) [Round(LogIntegral(n)): n in [2..80]]; // _G. C. Greubel_, May 16 2019

%o (Sage) [round(li(n)) for n in (2..80)] # _G. C. Greubel_, May 16 2019

%Y Cf. A047783 (floor), A047785 (ceiling).

%K nonn

%O 2,2

%A _N. J. A. Sloane_

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)