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%I #15 Jul 30 2015 22:05:01
%S 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,
%T 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,
%U 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
%N Decimal expansion of constant appearing in the expected number of comparisons for an unsuccessful digital tree search (negated).
%D Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.14 Digital Search Tree Constants, p. 355.
%H Vincenzo Librandi, <a href="/A086310/b086310.txt">Table of n, a(n) for n = 0..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TreeSearching.html">Tree Searching</a>
%F 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
%e -0.273948975138424613136884003782809045318148140...
%t 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 *)
%Y Cf. A065442, A086309.
%K nonn,cons
%O 0,1
%A _Eric W. Weisstein_, Jul 15 2003
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