OFFSET
1,2
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..2000
Eric Weisstein's World of Mathematics, Cosine Integral, Eq.20
FORMULA
Equals integral[-inf..+inf](exp(-x^2)*cos(k*x)) = sqrt(Pi/exp(k^2/2)), for k = 1.
EXAMPLE
1.38038844704314297477341524672559127427077246556221079845024685...
MATHEMATICA
RealDigits[N[Sqrt[Pi/Sqrt@ E], 120]] (* Michael De Vlieger, Apr 30 2015 *)
PROG
(PARI) a = sqrt(Pi/sqrt(exp(1)))
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Apr 28 2015
STATUS
approved