A convolution triangle of numbers obtained from A034255.

Terms

a(0) =1a(1) =10a(2) =1a(3) =120a(4) =20a(5) =1a(6) =1560a(7) =340a(8) =30a(9) =1a(10) =21216a(11) =5520a(12) =660a(13) =40a(14) =1a(15) =297024a(16) =88032a(17) =12880a(18) =1080a(19) =50a(20) =1a(21) =4243200a(22) =1392768a(23) =236448a(24) =24640a(25) =1600a(26) =60a(27) =1a(28) =61526400a(29) =21952320