A026875 T(2n,n+4), T given by A026758.
1, 10, 67, 379, 1959, 9597, 45448, 210514, 960942, 4344683, 19525389, 87444051, 390992168, 1747941216, 7821157977, 35055231757, 157484297780, 709447933434, 3205851742378, 14534550949750, 66123187204244, 301875869514852
Offset: 4