a(n) = Product_{k=0..n} (n^2 + k^2).A272244a(n) = Product_{k=0..n} (n^2 + k^2).Terms a(0) =0a(1) =2a(2) =160a(3) =21060a(4) =4352000a(5) =1313845000a(6) =547573478400External referencesoeis: A272244