A047129 T(2n,n), array T as in A047120.
1, 1, 6, 28, 166, 971, 5937, 36736, 230363, 1458037, 9292357, 59576614, 383721187, 2481397399, 16099317872, 104753149406, 683279530195, 4466548322041, 29253296829696, 191917744224242, 1260998821726319, 8296736705457073
Offset: 0