Column 3 of triangle in A250104 (or A124323).

Terms

a(0) =1a(1) =0a(2) =10a(3) =20a(4) =140a(5) =616a(6) =3444a(7) =19440a(8) =117975a(9) =753500a(10) =5068492a(11) =35764092a(12) =264044235a(13) =2034636800a(14) =16327586760a(15) =136180742640