Definition:Apéry's Constant/Historical Note

Historical Note on Apéry's Constant
Apéry's constant was first investigated by, who tried but failed to calculate its value.

Its precise value is still unknown.

However, in $1979$ published a proof that it is irrational.

The statement of this fact is now known as Apéry's Theorem, and the constant itself is known as Apéry's constant.