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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 38 |
| 5 | 147 |
| 6 | 587 |
| 7 | 2406 |
| 8 | 10215 |
| 9 | 43810 |
| 10 | 191420 |
| 11 | 846279 |
| 12 | 3777172 |
| 13 | 17035113 |
| 14 | 77322677 |
| 15 | 353531629 |
| 16 | 1625496758 |
| 17 | 7511140978 |
| 18 | 34874728630 |
| 19 | 162546596481 |
| 20 | 760497205550 |
| 21 | 3569629858872 |
| 22 | 16805317213158 |
| 23 | 79336544291945 |
| 24 | 375460389917649 |
| 25 | 1781012503780536 |
| 26 | 8466003357569875 |
| 27 | 40321831074573891 |
[1,1,3,11,38,147,587,2406,10215,43810,191420, 846279,3777172,17035113,77322677,353531629, 1625496758,7511140978,34874728630,162546596481, 760497205550,3569629858872,16805317213158, 79336544291945,375460389917649,1781012503780536, 8466003357569875,40321831074573891] |