Column 6 of triangle A117418.

Terms

a(0) =1a(1) =7a(2) =37a(3) =180a(4) =871a(5) =4296a(6) =21821a(7) =114676a(8) =624893a(9) =3529464a(10) =20644969a(11) =124886526a(12) =780450996a(13) =5030514429a(14) =33387021887a(15) =227809277707