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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 73 |
| 6 | 243 |
| 7 | 785 |
| 8 | 2511 |
| 9 | 8073 |
| 10 | 26312 |
| 11 | 87257 |
| 12 | 294603 |
| 13 | 1011602 |
| 14 | 3526519 |
| 15 | 12456315 |
| 16 | 44495535 |
| 17 | 160468964 |
| 18 | 583421709 |
| 19 | 2135814678 |
| 20 | 7865015071 |
| 21 | 29109558620 |
| 22 | 108213772256 |
| 23 | 403835324635 |
| 24 | 1512193773211 |
| 25 | 5679789173645 |
| 26 | 21391713994138 |
| 27 | 80767323230065 |
| 28 | 305638129059811 |
| 29 | 1158989815141334 |
| 30 | 4403331448837253 |
[1,1,2,6,21,73,243,785,2511,8073,26312,87257, 294603,1011602,3526519,12456315,44495535, 160468964,583421709,2135814678,7865015071, 29109558620,108213772256,403835324635, 1512193773211,5679789173645,21391713994138, 80767323230065,305638129059811,1158989815141334, 4403331448837253] |