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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 57 |
| 4 | 240 |
| 5 | 800 |
| 6 | 2226 |
| 7 | 5390 |
| 8 | 11712 |
| 9 | 23355 |
| 10 | 43450 |
| 11 | 76351 |
| 12 | 127920 |
| 13 | 205842 |
| 14 | 319970 |
| 15 | 482700 |
| 16 | 709376 |
| 17 | 1018725 |
| 18 | 1433322 |
| 19 | 1980085 |
| 20 | 2690800 |
| 21 | 3602676 |
| 22 | 4758930 |
| 23 | 6209402 |
| 24 | 8011200 |
| 25 | 10229375 |
| 26 | 12937626 |
| 27 | 16219035 |
| 28 | 20166832 |
| 29 | 24885190 |
| 30 | 30490050 |
[0,1,10,57,240,800,2226,5390,11712,23355,43450, 76351,127920,205842,319970,482700,709376,1018725, 1433322,1980085,2690800,3602676,4758930,6209402, 8011200,10229375,12937626,16219035,20166832, 24885190,30490050] |