a(n) = round( Gamma(n+3/4)/Gamma(3/4) ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =14a(5) =64a(6) =370a(7) =2495a(8) =19339a(9) =169215a(10) =1649844a(11) =17735823a(12) =208395916a(13) =2657047924a(14) =36534408953a(15) =538882532061