Cahen's constant

Cahen's constant is a mathematical constant that arises in the study of continued fractions and is denoted by the symbol \( C \). It can be defined as the sum of the reciprocals of the factorials of the natural numbers, specifically: \[ C = \sum_{n=0}^{\infty} \frac{1}{n!} \] This series converges to a value very close to the number \( e \) (the base of the natural logarithm).