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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 86 |
| 6 | 321 |
| 7 | 1085 |
| 8 | 3266 |
| 9 | 8797 |
| 10 | 21478 |
| 11 | 48206 |
| 12 | 100728 |
| 13 | 198046 |
| 14 | 369617 |
| 15 | 659505 |
| 16 | 1131656 |
| 17 | 1876481 |
| 18 | 3018946 |
| 19 | 4728382 |
| 20 | 7230242 |
| 21 | 10820046 |
| 22 | 15879769 |
| 23 | 22896941 |
| 24 | 32486742 |
| 25 | 45417389 |
| 26 | 62639126 |
| 27 | 85317142 |
| 28 | 114868756 |
| 29 | 153005222 |
| 30 | 201778521 |
[1,2,6,22,86,321,1085,3266,8797,21478,48206, 100728,198046,369617,659505,1131656,1876481, 3018946,4728382,7230242,10820046,15879769, 22896941,32486742,45417389,62639126,85317142, 114868756,153005222,201778521] |