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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 21 |
| 6 | 63 |
| 7 | 203 |
| 8 | 655 |
| 9 | 2225 |
| 10 | 7519 |
| 11 | 26279 |
| 12 | 91601 |
| 13 | 326873 |
| 14 | 1162873 |
| 15 | 4215645 |
| 16 | 15229413 |
| 17 | 55842223 |
| 18 | 204204265 |
| 19 | 755626769 |
| 20 | 2788876167 |
| 21 | 10398436275 |
| 22 | 38671589327 |
| 23 | 145061791275 |
| 24 | 542955212801 |
| 25 | 2047149292105 |
| 26 | 7702710310237 |
[1,1,1,3,7,21,63,203,655,2225,7519,26279,91601, 326873,1162873,4215645,15229413,55842223, 204204265,755626769,2788876167,10398436275, 38671589327,145061791275,542955212801, 2047149292105,7702710310237] |