I tried to solve the following equation to find an explicit expression for x in terms of n. But the answer is a long relation in terms of RootOf and _Z. 

(1/4)*((-x^2+1)*(-4*Pi*(x^2-1)+n*(x^4-2*x^2+5))*cosh(n*x)*sinh(Pi*x)+sinh(n*x)*((-x^2+1)*(-4*n*(x^2-1)+Pi*(x^4-2*x^2+5))*cosh(Pi*x)-2*x*(x^4-2*x^2-3)*sinh(Pi*x)))/(x^2-1)^2=0

Any comment is welcomed.