a(n) = (n!)^2.A001044a(n) = (n!)^2.Terms a(0) =1a(1) =1a(2) =4a(3) =36a(4) =576a(5) =14400a(6) =518400a(7) =25401600a(8) =1625702400a(9) =131681894400External referencesoeis: A001044