Column 2 of square array A136730.

Terms

a(0) =1a(1) =3a(2) =9a(3) =43a(4) =324a(5) =3510a(6) =50528a(7) =913377a(8) =19918602a(9) =509040779a(10) =14918466255a(11) =493115508126