Unsolved problem in mathematics:
What is the smallest Skewes's number?
Large number used in number theory
In number theory, Skewes's number is any of several large numbers used by the South African mathematician Stanley Skewes as upper bounds for the smallest natural number
for which
![{\displaystyle \pi (x)>\operatorname {li} (x),}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f0f12964d2a54bafacbf5b00030d0e1211b70e11)
where π is the prime-counting function and li is the logarithmic integral function. Skewes's number is much larger, but it is now known that there is a crossing between
and
near
It is not known whether it is the smallest crossing.