a(n) = Product_{k=0..2*n-1} (3*n+k+1).A384303a(n) = Product_{k=0..2*n-1} (3*n+k+1).Terms a(0) =1a(1) =20a(2) =5040a(3) =3603600a(4) =5079110400External referencesoeis: A384303