  In this note, we explore certain determinantal descriptions of the Robbins
numbers. Techniques used for this include continued fractions, Riordan arrays
and series inversion. Proven and conjectured representations involve the
determinants of both Hankel and symmetric matrices. In specific cases, links
are drawn to centered polygonal numbers, and to heptagons and nonagons. We
conjecture a Hankel transform determinant for the Robbins numbers related to
the Fibonacci and the Catalan numbers.
