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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 11 |
| 4 | 71 |
| 5 | 131 |
| 6 | 846 |
| 7 | 1561 |
| 8 | 10081 |
| 9 | 18601 |
| 10 | 120126 |
| 11 | 221651 |
| 12 | 1431431 |
| 13 | 2641211 |
| 14 | 17057046 |
| 15 | 31472881 |
| 16 | 203253121 |
| 17 | 375033361 |
| 18 | 2421980406 |
| 19 | 4468927451 |
| 20 | 28860511751 |
| 21 | 53252096051 |
| 22 | 343904160606 |
| 23 | 634556225161 |
| 24 | 4097989415521 |
[1,1,6,11,71,131,846,1561,10081,18601,120126, 221651,1431431,2641211,17057046,31472881, 203253121,375033361,2421980406,4468927451, 28860511751,53252096051,343904160606,634556225161, 4097989415521] |