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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 39 |
| 5 | 147 |
| 6 | 639 |
| 7 | 2857 |
| 8 | 12725 |
| 9 | 58081 |
| 10 | 270250 |
| 11 | 1268444 |
| 12 | 6009439 |
| 13 | 28736727 |
| 14 | 138401100 |
| 15 | 670641714 |
| 16 | 3268021317 |
| 17 | 16004012529 |
| 18 | 78716657052 |
| 19 | 388701645264 |
| 20 | 1926266491659 |
| 21 | 9576792342099 |
| 22 | 47753368809171 |
| 23 | 238759903786041 |
[1,1,2,10,39,147,639,2857,12725,58081,270250, 1268444,6009439,28736727,138401100,670641714, 3268021317,16004012529,78716657052,388701645264, 1926266491659,9576792342099,47753368809171, 238759903786041] |