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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 17 |
| 5 | 52 |
| 6 | 168 |
| 7 | 561 |
| 8 | 1922 |
| 9 | 6719 |
| 10 | 23871 |
| 11 | 85938 |
| 12 | 312823 |
| 13 | 1149421 |
| 14 | 4257460 |
| 15 | 15880036 |
| 16 | 59594517 |
| 17 | 224856450 |
| 18 | 852491806 |
| 19 | 3245959002 |
| 20 | 12407332166 |
| 21 | 47592364107 |
| 22 | 183139542306 |
| 23 | 706794663136 |
| 24 | 2735053815771 |
| 25 | 10609811267757 |
| 26 | 41251228784198 |
[1,1,2,6,17,52,168,561,1922,6719,23871,85938, 312823,1149421,4257460,15880036,59594517, 224856450,852491806,3245959002,12407332166, 47592364107,183139542306,706794663136, 2735053815771,10609811267757,41251228784198] |