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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 20 |
| 4 | 70 |
| 5 | 245 |
| 6 | 874 |
| 7 | 3164 |
| 8 | 11577 |
| 9 | 42694 |
| 10 | 158431 |
| 11 | 590873 |
| 12 | 2212797 |
| 13 | 8315535 |
| 14 | 31341163 |
| 15 | 118423810 |
| 16 | 448455754 |
| 17 | 1701534151 |
| 18 | 6467049185 |
| 19 | 24617030774 |
| 20 | 93834205107 |
| 21 | 358116770601 |
| 22 | 1368283768753 |
| 23 | 5233261657558 |
| 24 | 20034371696497 |
| 25 | 76763164565117 |
| 26 | 294357181436313 |
| 27 | 1129575035419485 |
[1,2,6,20,70,245,874,3164,11577,42694,158431, 590873,2212797,8315535,31341163,118423810, 448455754,1701534151,6467049185,24617030774, 93834205107,358116770601,1368283768753, 5233261657558,20034371696497,76763164565117, 294357181436313,1129575035419485] |