Andre Permutation Calculus; a Twin Seidel Matrix Sequence
  Entringer numbers occur in the Andr\'e permutation combinatorial set-up under several forms. This leads to the construction of a matrix-analog refinement of the tangent (resp. secant) numbers. Furthermore, closed expressions for the three-variate exponential generating functions for pairs of so-called Entringerian statistics are derived. 
Dominique Foata and Guo-Niu Han
math.CO