Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =6a(5) =3a(6) =1a(7) =12a(8) =24a(9) =4a(10) =1a(11) =20a(12) =90a(13) =80a(14) =5a(15) =1a(16) =30a(17) =240a(18) =540a(19) =240a(20) =6a(21) =1a(22) =42a(23) =525a(24) =2240a(25) =2835a(26) =672a(27) =7a(28) =1a(29) =56