%I #4 Jan 29 2013 18:26:18
%S 1,9,68,1364,12064,58303,4517375,1142991,4251679307,138473652271,
%T 240881487689,857560784067,49571162119157,12805922830496929,
%U 167798784068528807,365691567246838709,46160923354240494523
%N Numerator of the sum of all matrix elements of n X n matrix M[i,j]=CatalanNumber[i]/CatalanNumber[j], where CatalanNumber[k]=(2k)!/k!/(k+1)!=A000108[k].
%C p divides a(p-1) for primes p in A007645.
%F a(n) = Numerator[Sum[Sum[(2i)!/(i!)^2/(i+1)/((2j)!/(j!)^2/(j+1)),{i,1,n}],{j,1,n}]].
%t Numerator[Table[Sum[Sum[(2i)!/(i!)^2/(i+1)/((2j)!/(j!)^2/(j+1)),{i,1,n}],{j,1,n}],{n,1,20}]]
%Y Cf. A000108, A014138, A007645.
%K frac,nonn
%O 1,2
%A _Alexander Adamchuk_, Jul 14 2006