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

A144440

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

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =11a(5) =1a(6) =1a(7) =54a(8) =54a(9) =1a(10) =1a(11) =229a(12) =789a(13) =229a(14) =1a(15) =1a(16) =932a(17) =7975a(18) =7975a(19) =932a(20) =1a(21) =1a(22) =3747a(23) =68628a(24) =161867a(25) =68628a(26) =3747a(27) =1a(28) =1a(29) =15010

External references