Triangular array read by rows: T(n,1) = T(n,n) = 1, T(n,k) = 3*T(n-1,k-1) + 2*T(n-1,k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =1a(6) =1a(7) =13a(8) =17a(9) =1a(10) =1a(11) =29a(12) =73a(13) =53a(14) =1a(15) =1a(16) =61a(17) =233a(18) =325a(19) =161a(20) =1a(21) =1a(22) =125a(23) =649a(24) =1349a(25) =1297a(26) =485a(27) =1a(28) =1a(29) =253