Column 3 of triangle A318945.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =7a(7) =34a(8) =139a(9) =512a(10) =1757a(11) =5727a(12) =17952a(13) =54577