Jan 1, 2019
J. Comb. Theory, Ser. A
Abstract In the theory of finite type Vassiliev knot invariants, the universal sl 2 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.