a(n) = (n!)(n!-1)(n!-2)...(n!-n+1).A181760a(n) = (n!)(n!-1)(n!-2)...(n!-n+1).Terms a(0) =1a(1) =1a(2) =2a(3) =120a(4) =255024a(5) =22869362880External referencesoeis: A181760