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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 41 |
| 4 | 251 |
| 5 | 1546 |
| 6 | 9281 |
| 7 | 55936 |
| 8 | 335656 |
| 9 | 2015236 |
| 10 | 12091631 |
| 11 | 72557806 |
| 12 | 435346876 |
| 13 | 2612129211 |
| 14 | 15672776566 |
| 15 | 94036939331 |
| 16 | 564221643971 |
| 17 | 3385331551426 |
| 18 | 20311989308806 |
| 19 | 121871945977221 |
| 20 | 731231675909811 |
| 21 | 4387390115926096 |
| 22 | 26324340695837771 |
| 23 | 157946044538104906 |
[1,6,41,251,1546,9281,55936,335656,2015236, 12091631,72557806,435346876,2612129211, 15672776566,94036939331,564221643971, 3385331551426,20311989308806,121871945977221, 731231675909811,4387390115926096, 26324340695837771,157946044538104906] |