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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A247377 Decimal expansion of integral_{0..infinity} 1/Gamma(1+x) dx, a variation of the Fransén-Robinson constant. 1
2, 2, 6, 6, 5, 3, 4, 5, 0, 7, 6, 9, 9, 8, 4, 8, 8, 3, 5, 0, 7, 1, 9, 6, 3, 8, 5, 7, 6, 7, 8, 2, 2, 0, 9, 1, 8, 4, 0, 8, 8, 2, 9, 7, 1, 4, 2, 8, 0, 2, 2, 2, 1, 9, 3, 8, 6, 1, 0, 9, 3, 5, 5, 4, 4, 2, 9, 1, 8, 8, 9, 9, 7, 6, 9, 1, 3, 7, 5, 2, 8, 1, 0, 8, 5, 0, 9, 1, 0, 6, 9, 7, 4, 7, 9, 3, 4, 0, 6, 9, 5, 8, 8, 4 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 4.6 Fransén-Robinson constant, p. 263.

LINKS

Table of n, a(n) for n=1..104.

Eric Weisstein's MathWorld, Fransén-Robinson Constant

FORMULA

Also equals e - integral_{-infinity..infinity}  e^(-e^x)/(x^2 + Pi^2) dx (observed by Ramanujan).

EXAMPLE

2.266534507699848835071963857678220918408829714280222193861...

MATHEMATICA

NIntegrate[1/Gamma[1 + x], {x, 0, Infinity}, WorkingPrecision -> 104] // RealDigits // First

PROG

(Python)

from sympy.mpmath import *

mp.dps = 200

A247377 = [d for d in nstr(quad(lambda x:1/gamma(1+x), [0, inf]), n=mp.dps)[:-1] if d != '.'] # Chai Wah Wu, Sep 16 2014

CROSSREFS

Cf. A058655.

Sequence in context: A171661 A276418 A173869 * A167909 A185421 A219976

Adjacent sequences:  A247374 A247375 A247376 * A247378 A247379 A247380

KEYWORD

nonn,cons

AUTHOR

Jean-François Alcover, Sep 15 2014

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 19 11:31 EDT 2019. Contains 324219 sequences. (Running on oeis4.)