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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 7 |
| 2 | 36 |
| 3 | 235 |
| 4 | 1599 |
| 5 | 10948 |
| 6 | 75027 |
| 7 | 514231 |
| 8 | 3524580 |
| 9 | 24157819 |
| 10 | 165580143 |
| 11 | 1134903172 |
| 12 | 7778742051 |
| 13 | 53316291175 |
| 14 | 365435296164 |
| 15 | 2504730781963 |
| 16 | 17167680177567 |
| 17 | 117669030460996 |
| 18 | 806515533049395 |
| 19 | 5527939700884759 |
| 20 | 37889062373143908 |
| 21 | 259695496911122587 |
[3,7,36,235,1599,10948,75027,514231,3524580, 24157819,165580143,1134903172,7778742051, 53316291175,365435296164,2504730781963, 17167680177567,117669030460996,806515533049395, 5527939700884759,37889062373143908, 259695496911122587] |