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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 22 |
| 5 | 76 |
| 6 | 290 |
| 7 | 1225 |
| 8 | 5616 |
| 9 | 27758 |
| 10 | 147050 |
| 11 | 829926 |
| 12 | 4966258 |
| 13 | 31382572 |
| 14 | 208676004 |
| 15 | 1455540594 |
| 16 | 10620614461 |
| 17 | 80869622604 |
| 18 | 641177678068 |
| 19 | 5282866462839 |
| 20 | 45152445030267 |
| 21 | 399673570426188 |
| 22 | 3658433105500600 |
| 23 | 34582526451125235 |
| 24 | 337165886689229224 |
[1,1,3,7,22,76,290,1225,5616,27758,147050,829926, 4966258,31382572,208676004,1455540594,10620614461, 80869622604,641177678068,5282866462839, 45152445030267,399673570426188,3658433105500600, 34582526451125235,337165886689229224] |