TL;DR: An arithmetic triangle similar to Pascal's triangle is developed, interpreted in terms of numbers of pairs of nonintersecting paths in the first quadrant, with main applications about the Catalan numbers and various random walk problems.
TL;DR: In this article, a general approach to constructing small free Z Gamma-resolutions for certain infinite isometry groups Gamma is described. But this approach is not suitable for the infinite cyclic central extensions of triangle groups.
Abstract: We describe a general approach to constructing small free Z Gamma-resolutions for certain infinite isometry groups Gamma. We apply the method to a class of generalized triangle groups and use the resolution to compute the integral homology of these groups. In illustrating the method we also obtain resolutions for the classical triangle groups and for their infinite cyclic central extensions, considered previously by Strebel.
TL;DR: The doubloon polynomials are generating functions for a class of combinatorial objects called normalized doubloons by the compressed major index as mentioned in this paper, which provide a refinement of the q-tangent numbers and also involve two major specializations: the Poupard triangle and the Catalan triangle.
Abstract: The doubloon polynomials are generating functions for a class of combinatorial objects called normalized doubloons by the compressed major index. They provide a refinement of the q-tangent numbers and also involve two major specializations: the Poupard triangle and the Catalan triangle.