Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 1.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =2a(5) =1a(6) =0a(7) =3a(8) =6a(9) =1a(10) =0a(11) =4a(12) =24a(13) =12a(14) =1a(15) =0a(16) =5a(17) =80a(18) =90a(19) =20a(20) =1a(21) =0a(22) =6a(23) =240a(24) =540a(25) =240a(26) =30a(27) =1a(28) =0a(29) =7