OFFSET
0,1
FORMULA
Equals (sqrt(Pi)/2) * erf(1) = (sqrt(Pi)/(2*i)) * erfi(i).
Equals Sum_{k>=0} (-1)^k / ((2*k + 1)*k!). - Ilya Gutkovskiy, Sep 18 2021
EXAMPLE
0.74682413281242702539946743613185300535449968...
MATHEMATICA
RealDigits[(Sqrt[Pi]/2) Erf[1], 10, 91][[1]]
PROG
(PARI) intnum(x=0, 1, exp(-x^2)) \\ Michel Marcus, Sep 18 2021
CROSSREFS
KEYWORD
AUTHOR
Jianing Song, Sep 18 2021
STATUS
approved