a(n) = (10*n)!*(n/2)!/((5*n)!*(4*n)!*(3*n/2)!).A364179a(n) = (10*n)!*(n/2)!/((5*n)!*(4*n)!*(3*n/2)!).Terms a(0) =1a(1) =840a(2) =2771340a(3) =10754814720External referencesoeis: A364179