Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 2.

Terms

a(0) =1a(1) =2a(2) =1a(3) =3a(4) =6a(5) =1a(6) =4a(7) =24a(8) =12a(9) =1a(10) =5a(11) =80a(12) =90a(13) =20a(14) =1a(15) =6a(16) =240a(17) =540a(18) =240a(19) =30a(20) =1a(21) =7a(22) =672a(23) =2835a(24) =2240a(25) =525a(26) =42a(27) =1a(28) =8a(29) =1792