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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 52 |
| 5 | 473 |
| 6 | 5198 |
| 7 | 67567 |
| 8 | 1013512 |
| 9 | 17229713 |
| 10 | 327364538 |
| 11 | 6874655287 |
| 12 | 158117071612 |
| 13 | 3952926790313 |
| 14 | 106729023338438 |
| 15 | 3095141676814687 |
| 16 | 95949391981255312 |
| 17 | 3166329935381425313 |
| 18 | 110821547738349885938 |
| 19 | 4100397266318945779687 |
| 20 | 159915493386438885407812 |
[1,2,7,52,473,5198,67567,1013512,17229713, 327364538,6874655287,158117071612,3952926790313, 106729023338438,3095141676814687, 95949391981255312,3166329935381425313, 110821547738349885938,4100397266318945779687, 159915493386438885407812] |