OFFSET
1,2
FORMULA
Equals (sqrt(Pi)/2) * erfi(1) = (sqrt(Pi)/(2*i)) * erf(i).
Equals Sum_{k>=0} 1 / ((2*k + 1)*k!) . - Ilya Gutkovskiy, Sep 18 2021
EXAMPLE
1.462651745907181608804048586856988155...
MATHEMATICA
RealDigits[(Sqrt[Pi]/2) Erfi[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