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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 201 |
| 5 | 2996 |
| 6 | 57613 |
| 7 | 1357987 |
| 8 | 37921761 |
| 9 | 1224420067 |
| 10 | 44884358461 |
| 11 | 1841710133330 |
| 12 | 83634349451425 |
| 13 | 4164470926316377 |
| 14 | 225629247763909837 |
| 15 | 13214729079087267931 |
| 16 | 831997985912417838017 |
| 17 | 56038514134260089791916 |
| 18 | 4020820086886704204188797 |
[1,1,3,19,201,2996,57613,1357987,37921761, 1224420067,44884358461,1841710133330, 83634349451425,4164470926316377, 225629247763909837,13214729079087267931, 831997985912417838017,56038514134260089791916, 4020820086886704204188797] |