A086310 Decimal expansion of constant appearing in the expected number of comparisons for an unsuccessful digital tree search (negated).

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

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: A348721 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