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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 14 |
| 4 | 40 |
| 5 | 131 |
| 6 | 471 |
| 7 | 1829 |
| 8 | 7620 |
| 9 | 33902 |
| 10 | 160362 |
| 11 | 803065 |
| 12 | 4241457 |
| 13 | 23546969 |
| 14 | 137002658 |
| 15 | 833225728 |
| 16 | 5284731576 |
| 17 | 34881786097 |
| 18 | 239147833907 |
| 19 | 1700114999791 |
| 20 | 12512735023124 |
| 21 | 95205884573428 |
| 22 | 747892058653238 |
| 23 | 6058264178225451 |
[1,3,6,14,40,131,471,1829,7620,33902,160362, 803065,4241457,23546969,137002658,833225728, 5284731576,34881786097,239147833907,1700114999791, 12512735023124,95205884573428,747892058653238, 6058264178225451] |