T(2n+1,n+1), T given by A027011.

Terms

a(0) =1a(1) =5a(2) =28a(3) =98a(4) =291a(5) =806a(6) =2164a(7) =5729a(8) =15072a(9) =39542a(10) =103615a(11) =271370a(12) =710568a(13) =1860413a(14) =4870756a(15) =12751946a(16) =33385179a(17) =87403694a(18) =228826012a(19) =599074457a(20) =1568397480a(21) =4106118110a(22) =10749956983a(23) =28143752978a(24) =73681302096a(25) =192900153461a(26) =505019158444