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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 13 |
| 3 | 126 |
| 4 | 1476 |
| 5 | 17396 |
| 6 | 205363 |
| 7 | 2419304 |
| 8 | 28515138 |
| 9 | 336046126 |
| 10 | 3960336818 |
| 11 | 46672710626 |
| 12 | 550039863065 |
| 13 | 6482242131027 |
| 14 | 76393487374019 |
| 15 | 900300354854882 |
| 16 | 10610076292064874 |
| 17 | 125040180523981545 |
| 18 | 1473603611859143248 |
[0,13,126,1476,17396,205363,2419304,28515138, 336046126,3960336818,46672710626,550039863065, 6482242131027,76393487374019,900300354854882, 10610076292064874,125040180523981545, 1473603611859143248] |