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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 52 |
| 5 | 261 |
| 6 | 1374 |
| 7 | 7484 |
| 8 | 41860 |
| 9 | 239052 |
| 10 | 1388145 |
| 11 | 8171799 |
| 12 | 48658094 |
| 13 | 292541013 |
| 14 | 1773431121 |
| 15 | 10828258536 |
| 16 | 66531920611 |
| 17 | 411062356077 |
| 18 | 2552254837562 |
| 19 | 15916725942827 |
| 20 | 99656423131078 |
| 21 | 626202138247370 |
| 22 | 3947659825225371 |
| 23 | 24960745515499322 |
| 24 | 158256000235276253 |
[1,1,3,11,52,261,1374,7484,41860,239052,1388145, 8171799,48658094,292541013,1773431121,10828258536, 66531920611,411062356077,2552254837562, 15916725942827,99656423131078,626202138247370, 3947659825225371,24960745515499322, 158256000235276253] |