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A244067 Decimal expansion of the Purdom-Williams constant, a constant related to the Golomb-Dickman constant and to the asymptotic evaluation of the expectation of a random function longest cycle length. 5
7, 8, 2, 4, 8, 1, 6, 0, 0, 9, 9, 1, 6, 5, 6, 6, 1, 5, 0, 1, 6, 2, 1, 5, 1, 8, 8, 0, 6, 2, 9, 1, 0, 2, 8, 6, 6, 4, 4, 3, 0, 2, 8, 2, 5, 6, 6, 9, 6, 2, 8, 5, 8, 2, 4, 4, 1, 3, 7, 9, 2, 0, 3, 1, 9, 1, 7, 8, 0, 7, 1, 0, 9, 3, 0, 4, 0, 7, 4, 7, 3, 9, 1, 6, 5, 6, 9, 8, 8, 5, 2, 7, 3, 1, 0, 0, 3, 2, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.4.2 Random Mapping Statistics, p. 288.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..2500

Paul W. Purdom and John H. Williams, Cycle length in a random function, Transactions of the American Mathematical Society, Vol. 133, No. 2 (1968), pp. 547-551.

Eric Weisstein's MathWorld, Golomb-Dickman Constant.

Wikipedia, Golomb-Dickman constant.

FORMULA

Equals sqrt(Pi/2)*Integral_{x=0..1} exp(li(x)) dx, where li is the logarithmic integral function.

Equals A069998 * A084945. - Amiram Eldar, Aug 25 2020

EXAMPLE

0.78248160099165661501621518806291...

MATHEMATICA

lambda = Integrate[Exp[LogIntegral[x]], {x, 0, 1}]; N[lambda*Sqrt[Pi/2], 99] // RealDigits // First

CROSSREFS

Cf. A069998, A084945.

Sequence in context: A088367 A196610 A198938 * A225449 A345412 A021565

Adjacent sequences:  A244064 A244065 A244066 * A244068 A244069 A244070

KEYWORD

nonn,cons,easy

AUTHOR

Jean-François Alcover, Jun 19 2014

STATUS

approved

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Last modified August 5 04:03 EDT 2021. Contains 346457 sequences. (Running on oeis4.)