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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 21 |
| 5 | 61 |
| 6 | 199 |
| 7 | 659 |
| 8 | 2345 |
| 9 | 8569 |
| 10 | 32971 |
| 11 | 130527 |
| 12 | 538045 |
| 13 | 2279733 |
| 14 | 9987727 |
| 15 | 44897131 |
| 16 | 207693905 |
| 17 | 983926001 |
| 18 | 4780294291 |
| 19 | 23740460215 |
| 20 | 120595843941 |
| 21 | 625175300653 |
| 22 | 3308054119767 |
| 23 | 17837452131139 |
| 24 | 98006292402553 |
| 25 | 548026191197801 |
| 26 | 3118110841312091 |
[1,1,3,7,21,61,199,659,2345,8569,32971,130527, 538045,2279733,9987727,44897131,207693905, 983926001,4780294291,23740460215,120595843941, 625175300653,3308054119767,17837452131139, 98006292402553,548026191197801,3118110841312091] |