Triangle T(n, k) = (binomial(n-1, k-1)*binomial(n, k-1)/k) * ( 3^(k-1) if floor(n/2) >= k, otherwise 3^(n-k) ), read by rows.

A174346

Triangle T(n, k) = (binomial(n-1, k-1)*binomial(n, k-1)/k) * ( 3^(k-1) if floor(n/2) >= k, otherwise 3^(n-k) ), read by rows.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =9a(5) =1a(6) =1a(7) =18a(8) =18a(9) =1a(10) =1a(11) =30a(12) =180a(13) =30a(14) =1a(15) =1a(16) =45a(17) =450a(18) =450a(19) =45a(20) =1a(21) =1a(22) =63a(23) =945a(24) =4725a(25) =945a(26) =63a(27) =1a(28) =1a(29) =84

External references