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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 24 |
| 4 | 229 |
| 5 | 2449 |
| 6 | 28035 |
| 7 | 336100 |
| 8 | 4165920 |
| 9 | 52953884 |
| 10 | 686517601 |
| 11 | 9042628374 |
| 12 | 120669757468 |
| 13 | 1627932844657 |
| 14 | 22166277534398 |
| 15 | 304230231637560 |
| 16 | 4204474770868230 |
| 17 | 58458984141770754 |
| 18 | 817176088436608178 |
| 19 | 11477568712206346244 |
| 20 | 161897000202383717334 |
| 21 | 2292445680627209103645 |
[1,1,3,24,229,2449,28035,336100,4165920,52953884, 686517601,9042628374,120669757468,1627932844657, 22166277534398,304230231637560,4204474770868230, 58458984141770754,817176088436608178, 11477568712206346244,161897000202383717334, 2292445680627209103645] |