E^(-(1/12) + Derivative[1, 0][Zeta][-1, 1/2 + n])*Glaisher*BarnesG[3/2 + n]*Gamma[1/2 + n]^(-(1/2) - n) == 1 since Product[ -i+j+n, {i,n}, {j, 1-i+n}]== Product[(2*k-1)!/(k-1)!,{k,1,n}] according to A086205 and thus, again Product[(2 k - 1)!/(k - 1)! /(2 k - 1)^(n - k + 1), {k, n}] == 2^((n - 1) n/2) (* why? proof? *) ok, I’ll stop this now ;-) wouter.