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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 17 |
| 6 | 59 |
| 7 | 195 |
| 8 | 703 |
| 9 | 2499 |
| 10 | 9188 |
| 11 | 33895 |
| 12 | 126758 |
| 13 | 476269 |
| 14 | 1802311 |
| 15 | 6849776 |
| 16 | 26152417 |
| 17 | 100203193 |
| 18 | 385221142 |
| 19 | 1485200847 |
| 20 | 5741256763 |
| 21 | 22245940544 |
| 22 | 86383382826 |
| 23 | 336093325057 |
| 24 | 1309998125639 |
| 25 | 5114451441105 |
| 26 | 19998172734785 |
| 27 | 78306011677181 |
| 28 | 307022182222505 |
| 29 | 1205243866707467 |
| 30 | 4736694001644861 |
| 31 | 18635412907198669 |
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