I want to calculate such an integral $$ I=\int_0^{\infty}\int_0^\infty dx\,dy\ x^ny^m\exp(-ax^2-by^2-gxy+c_1x+c_2y), $$ where $a,b,g>0$ are positive and real, $n,m$ are positive integers and $c_1,c_2$ are arbitrary complex numbers. For sure I can firstly integrate over, say $y$, which is $$ \int_0^\infty dy\ y^m\exp(-by^2+(c_2-gx)y)\sim F\left(1+\frac{m}{2},\frac{3}{2},\frac{(c_2-gx)^2}{4b}\right) $$ where $F(\alpha,\gamma,z)$ is the Kummer Hypergeometric function. Now I havo to deal with the integral like this $$ \int_0^ \infty dx\ x^n\exp(-ax^2+c_1x) F\left(\alpha,\gamma,\frac{(c_2-gx)^2}{4b}\right). $$ How can I go on with it?
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1$\begingroup$ If you just need the integral for a few values of $m,n$, you could evaluate it with $m =0, n=0$ (in terms of erf( ) and differentiate w.r.t. $c_1$ and $c_2$ as needed to induce desired powers of $x$ and $y$. $\endgroup$– Tom DickensCommented Feb 9, 2023 at 2:16
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1$\begingroup$ en.wikipedia.org/wiki/Isserlis%27_theorem $\endgroup$– Steve HuntsmanCommented Feb 9, 2023 at 13:21
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