Column 1 of triangle A107884.

Terms

a(0) =1a(1) =3a(2) =9a(3) =37a(4) =210a(5) =1575a(6) =14943a(7) =173109a(8) =2381814a(9) =38087355a(10) =695745075a(11) =14317460370a(12) =328142173159