Triangular array formed from successive differences of factorial numbers.

Terms

a(0) =1a(1) =1a(2) =0a(3) =2a(4) =1a(5) =1a(6) =6a(7) =4a(8) =3a(9) =2a(10) =24a(11) =18a(12) =14a(13) =11a(14) =9a(15) =120a(16) =96a(17) =78a(18) =64a(19) =53a(20) =44a(21) =720a(22) =600a(23) =504a(24) =426a(25) =362a(26) =309a(27) =265a(28) =5040a(29) =4320