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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 262 |
| 3 | 3502 |
| 4 | 46741 |
| 5 | 621649 |
| 6 | 8240087 |
| 7 | 109043123 |
| 8 | 1441386411 |
| 9 | 19037866206 |
| 10 | 251285929522 |
| 11 | 3314574738534 |
| 12 | 43689000394782 |
| 13 | 575342418679410 |
[1,18,262,3502,46741,621649,8240087,109043123, 1441386411,19037866206,251285929522,3314574738534, 43689000394782,575342418679410] |