2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149096Value of generalized hypergeometric function at a special point is calculated. More precisely, value of certain multiple integral over vanishing cycle (all arguments collapse to unity) is calculated. The answer is expressed in terms of $Γ$-functions. The constant is relevant to the part of $ρ$ in the Gindikin-Karpelevich formula for c-function of Harish-Chandra. Calculation is an adaptation of classical calculations of Gelfand and Naimark (1950) to the Heckman-Opdam hypergeometric functions in the case of root system of type $A_{n-1}$.Ams-Tex error is corrected.High Energy Physics - Theorytext