OFFSET
1,1
COMMENTS
An approximation to Pi.
LINKS
J. M. Borwein, P. B. Borwein, and K. Dilcher, Pi, Euler numbers and asymptotic expansions, Amer. Math. Monthly, 96 (1989), 681-687.
J. M. Borwein and R. M. Corless, Review of "An Encyclopedia of Integer Sequences" by N. J. A. Sloane and Simon Plouffe, SIAM Review, 38 (1996), 333-337.
EXAMPLE
3.14157265358979523846264238327950410419716662937511592517489...
MATHEMATICA
First[RealDigits[4*Sum[(-1)^(k-1)/(2*k-1), {k, 50000}], 10, 100]] (* Paolo Xausa, May 11 2024 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
N. J. A. Sloane, Sep 08 2012
STATUS
approved