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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 20 |
| 5 | 18 |
| 6 | 12 |
| 7 | 126 |
| 8 | 33 |
| 9 | 204 |
| 10 | 1638 |
| 11 | 1968 |
| 12 | 2010 |
| 13 | 504 |
| 14 | 17043 |
| 15 | 240 |
| 16 | 222870 |
| 17 | 4084080 |
| 18 | 12462 |
| 19 | 81396 |
| 20 | 4200 |
| 21 | 41790 |
| 22 | 24254 |
| 23 | 56560 |
| 24 | 1377090 |
| 25 | 30669496 |
| 26 | 57420 |
| 27 | 249480 |
| 28 | 93840 |
| 29 | 696010 |
| 30 | 40680 |
| 31 | 4627497204 |
| 32 | 2122260 |
| 33 | 4774320 |
| 34 | 347190 |
| 35 | 83800 |
| 36 | 103458 |
| 37 | 5017446420 |
| 38 | 1686300 |
[1,2,4,20,18,12,126,33,204,1638,1968,2010,504, 17043,240,222870,4084080,12462,81396,4200,41790, 24254,56560,1377090,30669496,57420,249480,93840, 696010,40680,4627497204,2122260,4774320,347190, 83800,103458,5017446420,1686300] |