A047785 -id:A047785 - cp's OEIS frontend

A047783 a(n) = floor(Li(n)).

1, 2, 2, 3, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 23, 23

Offset: 2

N. J. A. Sloane

nonn

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.

Robert G. Wilson v, Table of n, a(n) for n = 2..1000
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

Cf. A047784 (round), A047785 (ceiling).

[Floor(LogIntegral(n)): n in [2..80]]; // G. C. Greubel, May 17 2019

Array[Floor[LogIntegral[#]] &, 70, 2] (* Robert G. Wilson v, Feb 23 2017 *)

vector(80, n, n++; floor(real(-eint1(-log(n)))) ) \\ G. C. Greubel, May 17 2019

[floor(li(n)) for n in (2..80)] # G. C. Greubel, May 17 2019

a(n) = floor(logarithmic integral(n)). - G. C. Greubel, May 17 2019

A047784 Nearest integer to Li(n).

Original entry on oeis.org

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, 13, 13, 14, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23

Offset: 2

N. J. A. Sloane

nonn

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.

G. C. Greubel, Table of n, a(n) for n = 2..10000
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].

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

[Round(LogIntegral(n)): n in [2..80]]; // G. C. Greubel, May 16 2019

Table[Round[LogIntegral[n]], {n, 2, 80}] (* G. C. Greubel, May 16 2019 *)

vector(80, n, n++; round(real(-eint1(-log(n)))) ) \\ G. C. Greubel, May 16 2019

[round(li(n)) for n in (2..80)] # G. C. Greubel, May 16 2019

a(n) = round(logarithmic integral(n)). - G. C. Greubel, May 16 2019

cp's OEIS Frontend

A047783 a(n) = floor(Li(n)).

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