Other representation of Gamma Incomplete function I have a question regarding Gamma Incomplete function:
In the "Table of Integrals, Series, and Products, Seventh Edition" equation $8.353.3$ page $900$, there is a defenition for the incomplete gamma function in the case $a < 1$ and $x > 0$
$$ \Gamma(a,x)=\frac{\rho^{-x}x^{a}}{\Gamma(1-a)} \int_0^\infty \frac{e^{-t} t^{-a}}{x+t} dt$$
what is $ \rho $ in the above equation? I thought this might be a but I tried to derive the above formula but I don't got the same result.

It should be $e$.  See the Handbook of Mathematical Functions, 8.6.4.
