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

Terms

a(0) =1a(1) =7a(2) =73a(3) =373a(4) =1404a(5) =4506a(6) =13226a(7) =36889a(8) =99947a(9) =266455a(10) =704150a(11) =1852212a(12) =4860468a(13) =12739243a(14) =33369709a(15) =87385081a(16) =228803856a(17) =599048334a(18) =1568366942a(19) =4106082685a(20) =10749916175a(21) =28143706267a(22) =73681248938a(23) =192900093288a(24) =505019090664