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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 103 |
| 3 | 1013 |
| 4 | 6855 |
| 5 | 42338 |
| 6 | 264239 |
| 7 | 1594229 |
| 8 | 8996095 |
| 9 | 47638710 |
| 10 | 240437466 |
| 11 | 1169737596 |
| 12 | 5509527123 |
| 13 | 25148632606 |
| 14 | 111340824937 |
| 15 | 478874919352 |
| 16 | 2004763896933 |
| 17 | 8184273650104 |
| 18 | 32633248916540 |
| 19 | 127260159420398 |
[20,103,1013,6855,42338,264239,1594229,8996095, 47638710,240437466,1169737596,5509527123, 25148632606,111340824937,478874919352, 2004763896933,8184273650104,32633248916540, 127260159420398] |