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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 42 |
| 3 | 351 |
| 4 | 3470 |
| 5 | 39968 |
| 6 | 528306 |
| 7 | 7906598 |
| 8 | 132426050 |
| 9 | 2457643895 |
| 10 | 50110693656 |
| 11 | 1114365815786 |
| 12 | 26856942480503 |
| 13 | 697612318151050 |
| 14 | 19435260247394150 |
| 15 | 578255661792065917 |
| 16 | 18303904706366202568 |
| 17 | 614296560055922433760 |
[1,6,42,351,3470,39968,528306,7906598,132426050, 2457643895,50110693656,1114365815786, 26856942480503,697612318151050,19435260247394150, 578255661792065917,18303904706366202568, 614296560055922433760] |