A125313 Decimal expansion of 2*exp(-gamma).

1, 1, 2, 2, 9, 1, 8, 9, 6, 7, 1, 3, 3, 7, 7, 0, 3, 3, 9, 6, 4, 8, 2, 8, 6, 4, 2, 9, 5, 8, 1, 7, 6, 1, 5, 7, 3, 5, 3, 1, 4, 2, 0, 7, 7, 3, 8, 5, 0, 3, 0, 6, 3, 3, 6, 3, 0, 8, 3, 1, 8, 1, 5, 2, 0, 9, 0, 1, 7, 5, 9, 3, 4, 1, 4, 8, 5, 7, 1, 2, 7, 4, 2, 6, 5, 7, 4, 2, 3, 1, 7, 8, 6, 8, 4, 2, 8, 7, 1, 7, 5, 3, 4, 6, 3

Offset: 1

Author

Robert G. Wilson v, Dec 08 2006

Keywords

• cons
• nonn

Examples

			1.12291896713377033964828642958176157353142077385030633630831815209...
		

References

• Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.3, Landau-Ramanujan constant, p. 100.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000
• A. Granville, Harald Cramér and the distribution of prime numbers, Scandinavian Actuarial Journal 1: 12-28, (1995) DOI:10.1080/03461238.1995.10413946.
• Bernard Montaron, Exponential prime sequences, arXiv:2011.14653 [math.NT], 2020.
• Simon Plouffe, Plouffe's Inverter.
• S. K. Wilson and B. R. Duffy, An asymptotic analysis of small holes in thin fluid layers, Journal of Engineering Mathematics, July 1996, Volume 30, Issue 4, pp 445-457.

Programs

Magma

R:= RealField(100); 2*Exp(-EulerGamma(R)); // G. C. Greubel, Sep 05 2018

Mathematica

RealDigits[2*Exp[-EulerGamma], 10, 111][[1]]

PARI

default(realprecision, 100); 2*exp(-Euler) \\ G. C. Greubel, Sep 05 2018

Formula

Equals 2*A080130, 2*A001113^(-A001620) and 2/A073004 = 2/A068985^A001620.

Equals A088540 * A088541. - Jean-François Alcover, Jun 04 2014

Equals exp(A002162 - A001620). - John W. Nicholson, Apr 03 2015