A027115 a(n) = T(n,0) + T(n,1) + ... + T(n,2n), T given by A027113.
1, 4, 11, 31, 87, 246, 700, 2003, 5758, 16616, 48102, 139625, 406214, 1184138, 3457771, 10112245, 29613029, 86824136, 254840534, 748725393, 2201731878, 6479790418, 19084605389, 56247812793, 165884498711, 489512360356
Offset: 0