Triangle read by rows: T(n,0)=1, T(n,n)=1, T(n, k) = 2*(n-k)*T(n-1, k-1) + 2*k*T(n-1, k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =1a(6) =1a(7) =12a(8) =12a(9) =1a(10) =1a(11) =30a(12) =96a(13) =30a(14) =1a(15) =1a(16) =68a(17) =564a(18) =564a(19) =68a(20) =1a(21) =1a(22) =146a(23) =2800a(24) =6768a(25) =2800a(26) =146a(27) =1a(28) =1a(29) =304