The name Lobachevsky's function is sometimes given to the function
 |
also denoted 
,
where 
is Clausen's integral.
Lobachevsky's Function
See also
Clausen Function, Clausen's IntegralExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Lobachevsky's Function." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/LobachevskysFunction.html