%I #21 Sep 02 2024 10:42:48

%S 1,2,7,5,5,4,7,7,3,6,4,1,7,2,1,5,3,7,8,8,0,1,3,4,3,1,9,7,4,6,7,8,5,4,

%T 7,9,0,7,3,0,7,8,1,4,3,7,4,9,4,7,2,6,1,4,3,9,4,4,8,7,3,2,6,4,6,3,1,6,

%U 4,6,9,2,5,6,4,3,0,0,8,6,4,1,6,0,4,6,2,5,2,7,5,9,5,4,2,9,3,4,5,6

%N Decimal expansion of the unique positive solution of Integral_{0..x} exp(-t^2/2) dt = 1.

%H Steven Finch, <a href="https://web.archive.org/web/20150405060634/http://www.people.fas.harvard.edu/~sfinch/csolve/av.pdf">Pattern-Avoiding Permutations</a> [Internet archive]

%H Steven Finch, <a href="/A240885/a240885.pdf">Pattern-Avoiding Permutations</a> [Cached copy, with permission]

%F Solution to sqrt(Pi/2)*erf(x/sqrt(2)) = 1.

%e 1.2755477364172...

%t RealDigits[Sqrt[2]*InverseErf[Sqrt[2/Pi]], 10, 100] // First

%o (PARI) a=sqrt(Pi/2); b=a-1; c=1/sqrt(2); solve(x=1,2, a*erfc(c*x)-b) \\ _Charles R Greathouse IV_, Sep 02 2024

%Y Cf. A052319, A071075, A111004, A200404, A263885.

%K nonn,cons

%O 1,2

%A _Jean-François Alcover_, Apr 14 2014