A328078(2*n+1).

Terms

a(0) =2a(1) =5a(2) =15a(3) =48a(4) =169a(5) =618a(6) =2319a(7) =8804a(8) =33649a(9) =129046a(10) =495779a(11) =1906520a(12) =7335029a(13) =28227578a(14) =108642983a(15) =418176700a(16) =1609656953a(17) =6196050718a(18) =23850681323a(19) =91809753632a(20) =353409321213