Triangle T(n,k) read by rows: T(n,1) = T(n,n)=1, otherwise T(n,k) = (3n-3k+1)*T(n-1,k-1) + k*(3k-2)*T(n-1,k), 1<=k<=n.

A166962

Triangle T(n,k) read by rows: T(n,1) = T(n,n)=1, otherwise T(n,k) = (3n-3k+1)*T(n-1,k-1) + k*(3k-2)*T(n-1,k), 1<=k<=n.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =12a(5) =1a(6) =1a(7) =103a(8) =69a(9) =1a(10) =1a(11) =834a(12) =2170a(13) =316a(14) =1a(15) =1a(16) =6685a(17) =53910a(18) =27830a(19) =1329a(20) =1a(21) =1a(22) =53496a(23) =1219015a(24) =1652300a(25) =281195a(26) =5412a(27) =1a(28) =1a(29) =427987

External references