login
This site is supported by donations to The OEIS Foundation.

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A276709 Decimal expansion of the derivative of logarithmic integral at its positive real root. 1
2, 6, 8, 4, 5, 1, 0, 3, 5, 0, 8, 2, 0, 7, 0, 7, 6, 5, 2, 5, 0, 2, 3, 8, 2, 6, 4, 0, 4, 8, 7, 2, 3, 8, 6, 8, 5, 3, 1, 0, 1, 7, 9, 7, 3, 4, 5, 9, 8, 5, 5, 1, 6, 3, 5, 2, 2, 0, 4, 1, 4, 8, 6, 4, 5, 0, 2, 6, 4, 1, 1, 3, 3, 6, 3, 1, 7, 6, 7, 2, 4, 4, 8, 9, 3, 6, 2, 5, 0, 2, 2, 0, 1, 2, 5, 4, 8, 5, 2, 1, 5, 3, 6, 5, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Since the real root location of li(x) is the Soldner's constant A070769, this constant equals 1/log(A070769). It is also the inverse of the unique real root A091723 of the exponential integral function Ei(x).

LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..2000

Eric Weisstein's World of Mathematics, Logarithmic Integral

Wikipedia, Logarithmic integral function

FORMULA

Equals 1/log(A070769) and 1/A091723.

EXAMPLE

2.68451035082070765250238264048723868531017973459855163522041486450...

MATHEMATICA

1/x/.FindRoot[ExpIntegralEi[x] == 0, {x, 1}, WorkingPrecision -> 104] (* Vaclav Kotesovec, Sep 27 2016 *)

PROG

(PARI) li(z) = {my(c=z+0.0*I); \\ Computes li(z) for any complex z

if(imag(c)<0, return(-Pi*I-eint1(-log(c))), return(+Pi*I-eint1(-log(c)))); }

a = 1/log(solve(x=1.1, 2.0, real(li(x)))) \\ Computes this constant

CROSSREFS

Cf. A070769, A091723, A257821.

Sequence in context: A067067 A119279 A048741 * A115317 A117932 A073411

Adjacent sequences:  A276706 A276707 A276708 * A276710 A276711 A276712

KEYWORD

nonn,cons

AUTHOR

Stanislav Sykora, Sep 15 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 26 06:20 EDT 2017. Contains 287080 sequences.