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%I #27 Dec 01 2023 15:49:06
%S 6,8,2,6,8,9,4,9,2,1,3,7,0,8,5,8,9,7,1,7,0,4,6,5,0,9,1,2,6,4,0,7,5,8,
%T 4,4,9,5,5,8,2,5,9,3,3,4,5,3,2,0,8,7,8,1,9,7,4,7,8,8,9,0,0,4,8,5,9,8,
%U 2,8,8,3,9,7,4,4,0,9,6,5,9,0,0,1,7,6,9,8,3,6,8,1,1,2,7,8,6,5,5,0,5,6,5,4,5
%N Decimal expansion of the fraction of a population falling within +- 1 standard deviation of the mean, assuming a normal distribution.
%H Rick L. Shepherd, <a href="/A178647/b178647.txt">Table of n, a(n) for n = 0..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Erf.html">Erf</a>
%H Wikipedia, <a href="http://en.wikipedia.org/wiki/68-95-99.7_rule">68-95-99.7 rule</a>
%F erf(1/sqrt(2)). - _Jean-François Alcover_, May 29 2013
%e 0.6826894921370858971704650912640758449558259334532087819747889004859...
%p erf(1/sqrt(2)) ; evalf(%) ; # _R. J. Mathar_, Mar 22 2016
%t RealDigits[(1 + Erf[1/Sqrt@2])/2 - (1 + Erf[ -1/Sqrt@2])/2, 10, 111][[1]] (* _Robert G. Wilson v_, Jun 01 2010 *)
%o (MATLAB) 0.5*(1+erf(1/sqrt(2)))- 0.5*(1+erf(-1/sqrt(2)))
%o (PARI) (erfc(-1/sqrt(2))-erfc(1/sqrt(2)))/2 \\ _Charles R Greathouse IV_, Sep 04 2012
%o (PARI) 1 - erfc(1/sqrt(2)) \\ _Rick L. Shepherd_, Mar 05 2014
%Y Cf. A110894 (2sigma), A270712 (3sigma).
%K nonn,cons
%O 0,1
%A _Joost de Winter_, May 31 2010
%E More terms from _Robert G. Wilson v_, Jun 01 2010
%E Edited by _N. J. A. Sloane_, Jun 07 2010
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