813155081070domain: NAppears in sequencesExpansion of g.f.: (1-4*x*C)/(1-5*x*C) where C = (1/2-1/2*(1-4*x)^(1/2))/x = g.f. for Catalan numbers A000108.at n=16A076026Number of Dyck excursions with catastrophes from (0,0) to (n,0).at n=31A369432