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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 31 |
| 5 | 157 |
| 6 | 915 |
| 7 | 6213 |
| 8 | 48240 |
| 9 | 423398 |
| 10 | 4147775 |
| 11 | 44882107 |
| 12 | 531564195 |
| 13 | 6837784087 |
| 14 | 94909482330 |
| 15 | 1413561537884 |
| 16 | 22482554909451 |
| 17 | 380269771734265 |
| 18 | 6815003300096013 |
| 19 | 128992737080703803 |
| 20 | 2571218642722865352 |
| 21 | 53835084737513866662 |
| 22 | 1181222084520177393143 |
[1,1,2,8,31,157,915,6213,48240,423398,4147775, 44882107,531564195,6837784087,94909482330, 1413561537884,22482554909451,380269771734265, 6815003300096013,128992737080703803, 2571218642722865352,53835084737513866662, 1181222084520177393143] |