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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 58 |
| 4 | 469 |
| 5 | 3805 |
| 6 | 30856 |
| 7 | 250237 |
| 8 | 2029363 |
| 9 | 16457674 |
| 10 | 133467985 |
| 11 | 1082394961 |
| 12 | 8777976592 |
| 13 | 71187390793 |
| 14 | 577313524879 |
| 15 | 4681881191290 |
| 16 | 37968990062941 |
| 17 | 307919861162197 |
| 18 | 2497159938701848 |
| 19 | 20251398321372709 |
| 20 | 164234227697925595 |
[0,1,7,58,469,3805,30856,250237,2029363,16457674, 133467985,1082394961,8777976592,71187390793, 577313524879,4681881191290,37968990062941, 307919861162197,2497159938701848, 20251398321372709,164234227697925595] |