1, 1, 6, 21, 71, 196, 532, 1301, 3101, 6956, 15217, 31951, 65670, 130914, 256150, 489690, 920905, 1699693, 3092751, 5540571, 9802091, 17114237, 29550346, 50444952, 85264328, 142682505, 236649524, 389033014, 634408230, 1026350152, 1648328017, 2628254619