$$\ \int_0^{\pi} \bigl(\sin(x)\bigr)^{2n-2k+1} e^{a\cos(x)} dx , \qquad ,n,k\in\mathbb Z,a\in\mathbb R.$$$$\ \int_0^{\pi} \bigl(\sin(x)\bigr)^{2n-2k+1} e^{a\cos(x)} dx , \qquad a,n,k\in\mathbb Z.$$ I tried to solve this integral by parts, but I didn't get any result. I look forward to your experience.