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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 73 |
| 4 | 751 |
| 5 | 8587 |
| 6 | 104425 |
| 7 | 1323952 |
| 8 | 17303503 |
| 9 | 231455104 |
| 10 | 3153167249 |
| 11 | 43597546197 |
| 12 | 610232050453 |
| 13 | 8629733401556 |
| 14 | 123114479858631 |
| 15 | 1769728635257503 |
| 16 | 25607523627970183 |
| 17 | 372688563309335806 |
| 18 | 5451995469296025115 |
| 19 | 80122698147986922194 |
| 20 | 1182341393088427774071 |
[1,2,9,73,751,8587,104425,1323952,17303503, 231455104,3153167249,43597546197,610232050453, 8629733401556,123114479858631,1769728635257503, 25607523627970183,372688563309335806, 5451995469296025115,80122698147986922194, 1182341393088427774071] |