Column 2 of triangle A115080.

Terms

a(0) =1a(1) =3a(2) =7a(3) =31a(4) =150a(5) =853a(6) =5251a(7) =35109a(8) =249332a(9) =1873214a(10) =14754858a(11) =121380083a(12) =1037889452a(13) =9197178411a(14) =84207477581a(15) =794810896751