OFFSET
2,2
REFERENCES
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.
LINKS
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].
FORMULA
a(n) = round(logarithmic integral(n)). - G. C. Greubel, May 16 2019
MATHEMATICA
Table[Round[LogIntegral[n]], {n, 2, 80}] (* G. C. Greubel, May 16 2019 *)
PROG
(PARI) vector(80, n, n++; round(real(-eint1(-log(n)))) ) \\ G. C. Greubel, May 16 2019
(Magma) [Round(LogIntegral(n)): n in [2..80]]; // G. C. Greubel, May 16 2019
(Sage) [round(li(n)) for n in (2..80)] # G. C. Greubel, May 16 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved