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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 10 |
| 4 | 39 |
| 5 | 61 |
| 6 | 180 |
| 7 | 300 |
| 8 | 1157 |
| 9 | 1823 |
| 10 | 5502 |
| 11 | 9282 |
| 12 | 35911 |
| 13 | 57101 |
| 14 | 174312 |
| 15 | 296536 |
| 16 | 1147657 |
| 17 | 1837307 |
| 18 | 5643506 |
| 19 | 9657582 |
| 20 | 37349067 |
| 21 | 60103305 |
| 22 | 185313180 |
| 23 | 318533124 |
| 24 | 1230555661 |
| 25 | 1988344759 |
| 26 | 6145979174 |
| 27 | 10601082970 |
| 28 | 40907870479 |
[1,2,6,10,39,61,180,300,1157,1823,5502,9282,35911, 57101,174312,296536,1147657,1837307,5643506, 9657582,37349067,60103305,185313180,318533124, 1230555661,1988344759,6145979174,10601082970, 40907870479] |