| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 210 |
| 2 | 8190 |
| 3 | 102830 |
| 4 | 570780 |
| 5 | 2140866 |
| 6 | 6527430 |
| 7 | 16213080 |
| 8 | 36584730 |
| 9 | 73035900 |
| 10 | 139912500 |
| 11 | 243455940 |
| 12 | 417269580 |
| 13 | 664812330 |
| 14 | 1050179130 |
| 15 | 1567036926 |
| 16 | 2347625490 |
| 17 | 3315827970 |
| 18 | 4752128290 |
| 19 | 6479581290 |
| 20 | 8930870676 |
| 21 | 11796130710 |
| 22 | 15862692300 |
| 23 | 20336924790 |
[1,210,8190,102830,570780,2140866,6527430, 16213080,36584730,73035900,139912500,243455940, 417269580,664812330,1050179130,1567036926, 2347625490,3315827970,4752128290,6479581290, 8930870676,11796130710,15862692300,20336924790] |