| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 7 |
| 2 | 140 |
| 3 | 2205 |
| 4 | 16408 |
| 5 | 78155 |
| 6 | 279972 |
| 7 | 823585 |
| 8 | 2097200 |
| 9 | 4783023 |
| 10 | 10000060 |
| 11 | 19487237 |
| 12 | 35831880 |
| 13 | 62748595 |
| 14 | 105413588 |
| 15 | 170859465 |
| 16 | 268435552 |
| 17 | 410338775 |
| 18 | 612220140 |
| 19 | 893871853 |
| 20 | 1280000120 |
| 21 | 1801088667 |
| 22 | 2494358020 |
| 23 | 3404825585 |
[0,7,140,2205,16408,78155,279972,823585,2097200, 4783023,10000060,19487237,35831880,62748595, 105413588,170859465,268435552,410338775,612220140, 893871853,1280000120,1801088667,2494358020, 3404825585] |