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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 40 |
| 6 | 154 |
| 7 | 631 |
| 8 | 2246 |
| 9 | 10476 |
| 10 | 71232 |
| 11 | 383220 |
| 12 | 1553841 |
| 13 | 8223567 |
| 14 | 58756725 |
| 15 | 338290401 |
| 16 | 1754330940 |
| 17 | 11744499990 |
| 18 | 103864469131 |
| 19 | 1220564280222 |
| 20 | 17394859369497 |
| 21 | 214311637862464 |
| 22 | 1891506713163679 |
| 23 | 10894997683415647 |
[1,1,2,5,14,40,154,631,2246,10476,71232,383220, 1553841,8223567,58756725,338290401,1754330940, 11744499990,103864469131,1220564280222, 17394859369497,214311637862464,1891506713163679, 10894997683415647] |