Diagonal of triangle A277295; a(n) = A277295(n+2,n).

Terms

a(0) =2a(1) =14a(2) =76a(3) =378a(4) =1808a(5) =8484a(6) =39446a(7) =182732a(8) =846248a(9) =3926338a(10) =18276832a(11) =85436832a(12) =401313288a(13) =1894847846a(14) =8994916236a(15) =42931067910a(16) =206002472336a(17) =993664391720