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| n | a(n) |
|---|---|
| 3 | 3 |
| 4 | 98 |
| 5 | 1080 |
| 6 | 7568 |
| 7 | 40976 |
| 8 | 187488 |
| 9 | 761600 |
| 10 | 2830848 |
| 11 | 9821952 |
| 12 | 32254464 |
| 13 | 101263360 |
| 14 | 306229248 |
| 15 | 897175552 |
| 16 | 2558058496 |
| 17 | 7123894272 |
| 18 | 19434569728 |
| 19 | 52063567872 |
| 20 | 137236709376 |
| 21 | 356550967296 |
| 22 | 914355126272 |
| 23 | 2317328842752 |
[3,98,1080,7568,40976,187488,761600,2830848, 9821952,32254464,101263360,306229248,897175552, 2558058496,7123894272,19434569728,52063567872, 137236709376,356550967296,914355126272, 2317328842752] |