%I #2 Mar 30 2012 18:37:09
%S 1,2,18,268,5320,129474,3700550,121016160,4448701704,181463572394,
%T 8130511993010,396880976034092,20963000461338000,1191187898025406514,
%U 72455444438093714542,4697146562744837487104,323299667265950287087968
%N Central terms of triangle A138271.
%Y Cf. A138271; A138272, A138273, A138274.
%K nonn
%O 0,2
%A _Paul D. Hanna_, Mar 11 2008