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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 44 |
| 4 | 256 |
| 5 | 1502 |
| 6 | 8912 |
| 7 | 53510 |
| 8 | 324352 |
| 9 | 1980332 |
| 10 | 12160008 |
| 11 | 75015162 |
| 12 | 464566144 |
| 13 | 2886488906 |
| 14 | 17985045464 |
| 15 | 112333392044 |
| 16 | 703119387648 |
| 17 | 4409231140086 |
| 18 | 27696141476336 |
| 19 | 174229516043630 |
| 20 | 1097501783152256 |
| 21 | 6921721148337452 |
| 22 | 43701895245221848 |
[1,2,8,44,256,1502,8912,53510,324352,1980332, 12160008,75015162,464566144,2886488906, 17985045464,112333392044,703119387648, 4409231140086,27696141476336,174229516043630, 1097501783152256,6921721148337452, 43701895245221848] |