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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 28 |
| 4 | 338 |
| 5 | 2440 |
| 6 | 11859 |
| 7 | 43943 |
| 8 | 134273 |
| 9 | 355568 |
| 10 | 843290 |
| 11 | 1832469 |
| 12 | 3708583 |
| 13 | 7075643 |
| 14 | 12844948 |
| 15 | 22348290 |
| 16 | 37479704 |
| 17 | 60870173 |
| 18 | 96100013 |
| 19 | 147953978 |
| 20 | 222724440 |
| 21 | 328568314 |
| 22 | 475923713 |
[0,3,28,338,2440,11859,43943,134273,355568,843290, 1832469,3708583,7075643,12844948,22348290, 37479704,60870173,96100013,147953978,222724440, 328568314,475923713] |