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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 5 |
| 3 | 105 |
| 4 | 1245 |
| 5 | 11075 |
| 6 | 82918 |
| 7 | 545544 |
| 8 | 3226809 |
| 9 | 17404018 |
| 10 | 86501661 |
| 11 | 399545336 |
| 12 | 1727261600 |
| 13 | 7031347337 |
| 14 | 27094936830 |
| 15 | 99286765543 |
[0,5,105,1245,11075,82918,545544,3226809,17404018, 86501661,399545336,1727261600,7031347337, 27094936830,99286765543] |