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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 22 |
| 4 | 112 |
| 5 | 556 |
| 6 | 2992 |
| 7 | 16416 |
| 8 | 93040 |
| 9 | 537004 |
| 10 | 3156300 |
| 11 | 18805948 |
| 12 | 113415860 |
| 13 | 690920348 |
| 14 | 4246311084 |
| 15 | 26297470908 |
| 16 | 163962253192 |
| 17 | 1028405157316 |
| 18 | 6484807032820 |
| 19 | 41086983729464 |
| 20 | 261446728122772 |
| 21 | 1670163037965324 |
| 22 | 10707288651740680 |
| 23 | 68867225024134936 |
| 24 | 444264596237129308 |
| 25 | 2873850125874850068 |
[1,1,6,22,112,556,2992,16416,93040,537004,3156300, 18805948,113415860,690920348,4246311084, 26297470908,163962253192,1028405157316, 6484807032820,41086983729464,261446728122772, 1670163037965324,10707288651740680, 68867225024134936,444264596237129308, 2873850125874850068] |