OFFSET
0,1
FORMULA
Equals Sum_{i>=0} (-1)^k/((1+2*k)*Pi^(1+2*k)).
From Wolfe Padawer, Feb 16 2023: (Start)
Equals arccot(Pi).
Equals arcsin(1/sqrt(Pi^2 + 1)).
Equals arccos(1/sqrt(1 + 1/Pi^2)). (End)
EXAMPLE
0.30816907111598493578699960803405309858963702926316931351366234390168...
MATHEMATICA
RealDigits[ArcTan[1/Pi], 10, 90][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Bruno Berselli, Nov 22 2013
STATUS
approved