Column 4 of table A125781.

Terms

a(0) =1a(1) =5a(2) =21a(3) =91a(4) =433a(5) =2307a(6) =13804a(7) =92433a(8) =688611a(9) =5670713a(10) =51291468a(11) =506502769a(12) =5430460072a(13) =62894124926a(14) =783259655434