Diagonal T(s,s) of triangle A059836.

Terms

a(0) =1a(1) =1a(2) =4a(3) =18a(4) =144a(5) =1200a(6) =14400a(7) =176400a(8) =2822400a(9) =45722880a(10) =914457600a(11) =18441561600a(12) =442597478400