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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 39 |
| 3 | 320 |
| 4 | 2907 |
| 5 | 28152 |
| 6 | 284907 |
| 7 | 2977116 |
| 8 | 31875708 |
| 9 | 347884085 |
| 10 | 3855802689 |
| 11 | 43283239650 |
| 12 | 491083601338 |
| 13 | 5622489637407 |
| 14 | 64877058557079 |
| 15 | 753705528179424 |
| 16 | 8808460811302728 |
| 17 | 103487549564845200 |
| 18 | 1221565052783161763 |
| 19 | 14480208437556590346 |
| 20 | 172299129911222223324 |
[1,6,39,320,2907,28152,284907,2977116,31875708, 347884085,3855802689,43283239650,491083601338, 5622489637407,64877058557079,753705528179424, 8808460811302728,103487549564845200, 1221565052783161763,14480208437556590346, 172299129911222223324] |