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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 36 |
| 4 | 216 |
| 5 | 961 |
| 6 | 5977 |
| 7 | 39363 |
| 8 | 271564 |
| 9 | 1949165 |
| 10 | 14487241 |
| 11 | 111115804 |
| 12 | 877086405 |
| 13 | 7109569724 |
| 14 | 59075905996 |
| 15 | 502464618671 |
| 16 | 4369068613929 |
| 17 | 38796820526316 |
| 18 | 351496911119002 |
| 19 | 3246426019892427 |
| 20 | 30543990287835441 |
[1,1,6,36,216,961,5977,39363,271564,1949165, 14487241,111115804,877086405,7109569724, 59075905996,502464618671,4369068613929, 38796820526316,351496911119002,3246426019892427, 30543990287835441] |