After some long derivations with a certain 1D Hamiltonian, I end up with the following sum $$\sum_{n=2}^\infty \frac{1}{e^{an^2(1+\frac{b}{4n^2-1})}-1}$$ But I am completely stumped by the $(1+\frac{b}{4n^2-1})$ term. Is there any trick I can use to compute this sum?
I am interested in the behavior of the sum with respect to $a$
$a$ and $b$ are positive constants.
f[a_?NumericQ, b_?NumericQ] := NSum[1/(Exp[a*n^2*(1 + b/(4 n^2 - 1))] - 1), {n, 2, Infinity}], then e.g.f[0.4, 0.5]results in0.264993. – user64494 Mar 16 '22 at 11:59