Polynomials P_k(x) which form the Sheffer sequence for g(t) | = | (2t)/(e^t - 1) f(t) | = | (e^t - 1)/(e^t + 1) and have generating function sum_(k = 0)^∞ (P_k(x))/(k!) t^k = t/(1 - t) ((1 + t)/(1 - t))^x.

Mittag-Leffler polynomial | Sheffer sequence