2,8

Eventually contains negative terms!

The logarithmic integral is the "American" version starting at 0.

The first crossover (P. Demichel) is expected to be around 1.397162914*10^316. - Daniel Forgues, Oct 29 2011

Harry J. Smith, Table of n, a(n) for n = 2..20000

C. Caldwell, How many primes are there?

Patrick Demichel, The prime counting function and related subjects, April 05, 2005, 75 pages.

Eric Weisstein's World of Mathematics, Prime Counting Function

Eric Weisstein's World of Mathematics, Logarithmic Integral

Eric Weisstein's World of Mathematics, Skewes Number

Table[Round[LogIntegral[x]-PrimePi[x]], {x, 2, 100}]

(PARI) a(n)=round(real(-eint1(-log(n)))-primepi(n)) \\ Charles R Greathouse IV, Oct 28 2011

Cf. A052434.

Sequence in context: A063982 A318882 A055020 * A094701 A210452 A240301

Adjacent sequences: A052432 A052433 A052434 * A052436 A052437 A052438

sign

Eric W. Weisstein

approved