A Method for Obtaining Generating Function for Central Coefficients of   Triangles
  We present techniques for obtaining a generating function for the central coefficients of a triangle $T(n,k)$, which is given by the expression $[xH(x)]^k=\sum_{n\geqslant k} T(n,k)x^n$, $H(0)\neq 0$. We also prove certain theorems for solving direct and inverse problems. 
Vladimir Kruchinin and Dmitry Kruchinin
math.CO