We establish an integral representation for the Dirichlet generating function of the coefficients of Euler's pentagonal number theorem. The Bromwich-type integral enables analytic continuation to the entire complex plane, filling a gap in the literature and providing a new framework for studying the sequence's analytic structure. Furthermore, we derive the asymptotic behavior as the variable tends to negative infinity, and give integral representations for the Euler function $φ(q)$ and the Dedekind eta function $η(τ)$. Moreover, we obtain an explicit formula for the Dirichlet generating function at each positive integer, expressed as a finite sum.