Conway's twentieth-century mathematical curiosity, but it's still in use today.
This included the Schwarzschild solution as a special case, but it was considered to have no physical significance and it too remained a mathematical curiosity.
"These are a mathematical curiosity, a type of 'trick' dice that confound most people's ideas about probability."
The book delves into the lives of amateur mathematicians and describes odd mathematical curiosities.
Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity.
There is such a thing as mathematical curiosity, a rare and beautiful gift, often seen in children and nearly always fading out as they grow.
Perhaps one of the other AAS folks will give you the actual numbers to help you with your mathematical curiosity.
A consequence is that black holes are not merely a mathematical curiosity, but could result from any spherical star having sufficient mass.
It's one of those mathematical curiosities that are probably meaningless.