%0 Journal Article
%T A short proof of the Deutsch-Sagan congruence for connected non crossing graphs
%A Ira M. Gessel
%J Mathematics
%D 2014
%I arXiv
%X We give a short proof, using Lagrange inversion, of a congruence modulo 3 for the number of connected noncrossing graphs on n vertices that was conjectured by Emeric Deutsch and Bruce Sagan. A more complicated proof had been given earlier by S.-P. Eu, S.-C. Liu, and Y.-N. Yeh.
%U http://arxiv.org/abs/1403.7656v1