Triangle read by rows. T(n, k) = binomial(n, k) * n!^2 / floor(n/2)!^2.

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =8a(5) =4a(6) =36a(7) =108a(8) =108a(9) =36a(10) =144a(11) =576a(12) =864a(13) =576a(14) =144a(15) =3600a(16) =18000a(17) =36000a(18) =36000a(19) =18000a(20) =3600a(21) =14400a(22) =86400a(23) =216000a(24) =288000a(25) =216000a(26) =86400a(27) =14400a(28) =705600a(29) =4939200