The Euler-Mascheroni constant is a mathematical constant, used mainly in number theory, and is defined as the limiting difference between the harmonic series and the natural logarithm:
- γ = limn→∞ ( (Σk=1 to n 1/k) - ln(n) )
Intriguingly, the constant is also given by:
- γ = - ∫0∞ ln(x)/ex dx
Its value is approximately
- γ ≈ 0.57721566...
It is not known whether γ is rational or not.