%I A120277
%S A120277 6,160,2842,44868,681604,10248992,154149762,2327405740,35305388536,
%T A120277 538000530912,8231764528156,126399786937760,1946868985459272,
%U A120277 30066806831424448,465425347391123282,7219408741591089660
%N A120277 Sum of all matrix elements of n X N matrix M[i,j]=(2n+i+j)!/(n+i)!/(n+j)!, 
               i,j=1..n.
%C A120277 p divides a((p-1)/2) for prime p>2.
%F A120277 a(n) = Sum[Sum[(2n+i+j)!/(n+i)!/(n+j)!,{i,1,n}],{j,1,n}].
%t A120277 Table[Sum[Sum[(2n+i+j)!/(n+i)!/(n+j)!,{i,1,n}],{j,1,n}],{n,1,20}]
%Y A120277 Sequence in context: A157626 A128120 A030449 this_sequence A015086 A052466 
               A078535
%Y A120277 Adjacent sequences: A120274 A120275 A120276 this_sequence A120278 A120279 
               A120280
%K A120277 nonn
%O A120277 1,1
%A A120277 Alexander Adamchuk (alex(AT)kolmogorov.com), Jul 04 2006