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A057754 Integer nearest to Li(10^n), where Li(x) = integral(0..x, dt/log(t)). +0
4
6, 30, 178, 1246, 9630, 78628, 664918, 5762209, 50849235, 455055615, 4118066401, 37607950281, 346065645810, 3204942065692, 29844571475288, 279238344248557, 2623557165610822, 24739954309690415, 234057667376222382 (list; graph; listen)
OFFSET

1,1

COMMENT

"Li[z] is central to the study of the distribution of primes in number theory. The logarithmic integral function is sometimes also denoted by Li(z). In some number-theoretical applications li(z) is defined as [integral from 2 to z of 1/log(t) dt], with no principal value taken. This differs from the definition used in 'Mathematica' by the constant li(2)."

LINKS

C. Caldwell, values of pi(x)

B. Riemann, On the Number of Prime Numbers 1859, last page (various transcripts)

Stephen Wolfram, The Mathematica 3 Book, 1996, Section 3.2.10: Special Functions.

FORMULA

a(n) = round( Li( 10^n )) = round( Ei( ln( 10^n )))

EXAMPLE

Li( 10^22 ) = 201467286691248261498.15... => a(22)

pi( 10^22 ) = 201467286689315906290

MATHEMATICA

Table[ Round[ LogIntegral[ 10^n ] ], {n, 1, 25} ]

CROSSREFS

A052435( 10^n ) = a(n) - pi( 10^n ) for n > 0. Cf. A000720, A007504.

Sequence in context: A110706 A001341 A089896 this_sequence A001473 A063888 A029571

Adjacent sequences: A057751 A057752 A057753 this_sequence A057755 A057756 A057757

KEYWORD

nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 30 2000

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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