A convolution triangle of numbers obtained from A025751.

Terms

a(0) =1a(1) =15a(2) =1a(3) =330a(4) =30a(5) =1a(6) =8415a(7) =885a(8) =45a(9) =1a(10) =232254a(11) =26730a(12) =1665a(13) =60a(14) =1a(15) =6735366a(16) =825858a(17) =58320a(18) =2670a(19) =75a(20) =1a(21) =202060980a(22) =25992252a(23) =2003562a(24) =106560a(25) =3900a(26) =90a(27) =1a(28) =6213375135a(29) =830282805