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A086309 Decimal expansion of constant appearing in the expected number of comparisons for a successful digital tree search (negated). 2
7, 1, 6, 6, 4, 4, 0, 1, 6, 0, 2, 7, 3, 8, 8, 0, 2, 0, 4, 9, 6, 8, 0, 8, 6, 8, 4, 7, 8, 4, 7, 0, 1, 1, 8, 2, 7, 4, 4, 7, 9, 4, 0, 9, 4, 6, 3, 2, 4, 1, 4, 2, 6, 8, 2, 8, 2, 0, 3, 0, 7, 6, 3, 0, 3, 7, 9, 4, 6, 2, 8, 8, 4, 7, 8, 5, 7, 5, 9, 2, 8, 1, 6, 1, 0, 3, 5, 8, 2, 4, 2, 1, 9, 2, 3, 1, 2, 8, 9, 9, 2, 6 (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

3/2 + (gamma-1)/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

-0.7166440160273880204968086847847011827447940946...

MATHEMATICA

digits = 102; alpha = NSum[1/(2^k-1), {k, 1, 500}, NSumTerms -> 100, WorkingPrecision -> digits+10]; RealDigits[3/2 + (EulerGamma-1)/Log[2] - alpha, 10, digits] // First (* Jean-François Alcover, Jul 29 2014 *)

CROSSREFS

Cf. A065442, A086310.

Sequence in context: A176438 A092615 A199279 * A255888 A060625 A145423

Adjacent sequences:  A086306 A086307 A086308 * A086310 A086311 A086312

KEYWORD

nonn,cons

AUTHOR

Eric W. Weisstein, Jul 15 2003

STATUS

approved

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Last modified February 20 04:29 EST 2020. Contains 332063 sequences. (Running on oeis4.)