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A086310 Decimal expansion of constant appearing in the expected number of comparisons for an unsuccessful digital tree search (negated). 2
2, 7, 3, 9, 4, 8, 9, 7, 5, 1, 3, 8, 4, 2, 4, 6, 1, 3, 1, 3, 6, 8, 8, 4, 0, 0, 3, 7, 8, 2, 8, 0, 9, 0, 4, 5, 3, 1, 8, 1, 4, 8, 1, 4, 0, 4, 7, 9, 4, 2, 8, 3, 3, 4, 1, 4, 6, 5, 8, 1, 3, 5, 6, 1, 0, 6, 8, 3, 7, 0, 6, 9, 2, 9, 7, 3, 9, 0, 8, 4, 8, 2, 7, 5, 5, 0, 9, 2, 0, 1, 3, 2, 5, 7, 2, 4, 9, 4, 5, 4, 2, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.14 Digital Search Tree Constants, p. 355.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, Tree Searching

FORMULA

1/2 + gamma/log(2) - alpha, where gamma is Euler's constant and alpha is the Erdős-Borwein constant (A065442). - Jean-François Alcover, Jul 29 2014, after Steven Finch

EXAMPLE

-0.273948975138424613136884003782809045318148140...

MATHEMATICA

digits = 102; alpha =  NSum[1/(2^k-1), {k, 1, 500}, NSumTerms -> 100, WorkingPrecision -> digits+10]; RealDigits[1/2 + EulerGamma/Log[2] - alpha, 10, digits] // First (* Jean-François Alcover, Jul 29 2014 *)

CROSSREFS

Cf. A065442, A086309.

Sequence in context: A021789 A199160 A091694 * A115949 A209121 A021891

Adjacent sequences:  A086307 A086308 A086309 * A086311 A086312 A086313

KEYWORD

nonn,cons

AUTHOR

Eric W. Weisstein, Jul 15 2003

STATUS

approved

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Last modified September 21 07:28 EDT 2021. Contains 347596 sequences. (Running on oeis4.)