A generalization of the Kreweras triangle through the universal sl2 weight system

Abstract

In the theory of finite type Vassiliev knot invariants, the universal sl2 weight system maps the chord diagrams to polynomials in a single variable with integer coefficients. In this paper, we define a family of polynomials that generalize the Kreweras triangle (known to refine the normalized median Genocchi numbers), and we show how it appears in this weight system.