Column 2 of triangle in A250104 (or A124323).

Terms

a(0) =1a(1) =0a(2) =6a(3) =10a(4) =60a(5) =231a(6) =1148a(7) =5832a(8) =32175a(9) =188375a(10) =1169652a(11) =7663734a(12) =52808847a(13) =381494400a(14) =2881338840a(15) =22696790440a(16) =186058768140