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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 64 |
| 4 | 691 |
| 5 | 8506 |
| 6 | 117586 |
| 7 | 1811902 |
| 8 | 30977059 |
| 9 | 585159526 |
| 10 | 12157511122 |
| 11 | 276365651992 |
| 12 | 6835179127294 |
| 13 | 182885413524568 |
| 14 | 5265255383238592 |
| 15 | 162296482607602714 |
| 16 | 5332203008816278819 |
| 17 | 185989603728568482598 |
| 18 | 6863252473075010369626 |
| 19 | 267102762222709967674384 |
| 20 | 10932746393513621360731066 |
[1,1,7,64,691,8506,117586,1811902,30977059, 585159526,12157511122,276365651992,6835179127294, 182885413524568,5265255383238592, 162296482607602714,5332203008816278819, 185989603728568482598,6863252473075010369626, 267102762222709967674384, 10932746393513621360731066] |