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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 41 |
| 5 | 141 |
| 6 | 537 |
| 7 | 2041 |
| 8 | 8042 |
| 9 | 32028 |
| 10 | 129780 |
| 11 | 531331 |
| 12 | 2198502 |
| 13 | 9171233 |
| 14 | 38545677 |
| 15 | 163031436 |
| 16 | 693470737 |
| 17 | 2964491394 |
| 18 | 12729640115 |
| 19 | 54881425222 |
| 20 | 237471970199 |
| 21 | 1030935383055 |
| 22 | 4489081879021 |
| 23 | 19601108680782 |
| 24 | 85803380983100 |
| 25 | 376481393024385 |
| 26 | 1655473716162471 |
[1,1,4,11,41,141,537,2041,8042,32028,129780, 531331,2198502,9171233,38545677,163031436, 693470737,2964491394,12729640115,54881425222, 237471970199,1030935383055,4489081879021, 19601108680782,85803380983100,376481393024385, 1655473716162471] |