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| n | a(n) |
|---|---|
| 1 | 10 |
| 2 | 100 |
| 3 | 450 |
| 4 | 1953 |
| 5 | 9338 |
| 6 | 41433 |
| 7 | 177909 |
| 8 | 774134 |
| 9 | 3350020 |
| 10 | 14367500 |
| 11 | 61642245 |
| 12 | 264469320 |
| 13 | 1132543047 |
| 14 | 4847303685 |
| 15 | 20747148598 |
| 16 | 88770363000 |
| 17 | 379728672366 |
| 18 | 1624285944365 |
| 19 | 6947428890150 |
| 20 | 29713533493473 |
| 21 | 127078745348389 |
[10,100,450,1953,9338,41433,177909,774134,3350020, 14367500,61642245,264469320,1132543047,4847303685, 20747148598,88770363000,379728672366, 1624285944365,6947428890150,29713533493473, 127078745348389] |