cp's OEIS Frontend

A245422 Decimal expansion of the coefficient c appearing in the expression of the asymptotic expected shortest cycle in a random n-cyclation as c*sqrt(n).

%I A245422 #57 Jan 17 2020 05:45:29
%S A245422 1,4,5,7,2,7,0,8,7,9,2,7,3,6,5,3,8,5,3,6,9,4,4,5,4,0,6,8,1,2,0,0,4,7,
%T A245422 0,5,9,6,6,0,5,3,0,0,2,0,2,3,5,2,2,4,6,5,9,2,1,3,2,9,7,0,8,0,7,3,9,7,
%U A245422 9,8,3,7,3,9,7,3,2,2,0,0,0,1,8,2,0,5,8,7,9,5,8,3,0,9,6,8,4,0,3,4,5,1
%N A245422 Decimal expansion of the coefficient c appearing in the expression of the asymptotic expected shortest cycle in a random n-cyclation as c*sqrt(n).
%H A245422 Steven R. Finch, <a href="http://arxiv.org/abs/2001.00578">Errata and Addenda to Mathematical Constants</a>, p. 35.
%H A245422 Nicholas Pippenger, <a href="http://arxiv.org/abs/math/0408031">Random cyclations</a>, arXiv:math /0408031 [math.CO]
%F A245422 (sqrt(Pi)/2)*integral_{0..infinity} exp(-x - Ei(-x)/2), where Ei is the exponential integral function.
%e A245422 1.457270879273653853694454068120047059660530020235224659213297...
%t A245422 digits = 102; (Sqrt[Pi]/2)*NIntegrate[Exp[-x - ExpIntegralEi[-x]/2], {x, 0, Infinity}, WorkingPrecision -> digits+10] // RealDigits[#, 10, digits]& // First
%Y A245422 Cf. A143297 (analog in the case of the expected *longest* cycle in a random cyclation).
%K A245422 nonn,cons,easy
%O A245422 1,2
%A A245422 _Jean-François Alcover_, Sep 08 2014