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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 20 |
| 6 | 46 |
| 7 | 232 |
| 8 | 501 |
| 9 | 2352 |
| 10 | 24442 |
| 11 | 53243 |
| 12 | 550863 |
| 13 | 2616338 |
| 14 | 5701553 |
| 15 | 27077005 |
| 16 | 280237217 |
| 17 | 2900328380 |
| 18 | 6320545915 |
| 19 | 65414893802 |
| 20 | 310664269401 |
| 21 | 677015556295 |
| 22 | 7006815193063 |
| 23 | 33276323565116 |
| 24 | 344395408399372 |
| 25 | 7767597342090622 |
| 26 | 36889382062795742 |
[1,1,3,6,20,46,232,501,2352,24442,53243,550863, 2616338,5701553,27077005,280237217,2900328380, 6320545915,65414893802,310664269401,677015556295, 7006815193063,33276323565116,344395408399372, 7767597342090622,36889382062795742] |