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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 65 |
| 4 | 1059 |
| 5 | 23232 |
| 6 | 642859 |
| 7 | 21507733 |
| 8 | 844701160 |
| 9 | 38108248719 |
| 10 | 1942394699283 |
| 11 | 110401966739110 |
| 12 | 6923805346540685 |
| 13 | 474957822716470901 |
| 14 | 35377953843680999326 |
| 15 | 2843665890900123673997 |
| 16 | 245340865605247369255751 |
| 17 | 22614510471168438300336440 |
| 18 | 2217985444621941684970200607 |
[1,1,6,65,1059,23232,642859,21507733,844701160, 38108248719,1942394699283,110401966739110, 6923805346540685,474957822716470901, 35377953843680999326,2843665890900123673997, 245340865605247369255751, 22614510471168438300336440, 2217985444621941684970200607] |