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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 34 |
| 6 | 139 |
| 7 | 643 |
| 8 | 3198 |
| 9 | 17186 |
| 10 | 98438 |
| 11 | 598551 |
| 12 | 3842893 |
| 13 | 25957607 |
| 14 | 183858842 |
| 15 | 1361853786 |
| 16 | 10523285935 |
| 17 | 84648613474 |
| 18 | 707461189513 |
| 19 | 6132612218266 |
| 20 | 55050390426042 |
| 21 | 510994289786018 |
| 22 | 4898133459331104 |
| 23 | 48424584171850411 |
[1,1,3,9,34,139,643,3198,17186,98438,598551, 3842893,25957607,183858842,1361853786,10523285935, 84648613474,707461189513,6132612218266, 55050390426042,510994289786018,4898133459331104, 48424584171850411] |