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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 4 |
| 4 | 7 |
| 5 | 137 |
| 6 | 555 |
| 7 | 2912 |
| 8 | 18027 |
| 9 | 38966 |
| 10 | 95959 |
| 11 | 230884 |
| 12 | 326843 |
| 13 | 884570 |
| 14 | 1211413 |
| 15 | 2095983 |
| 16 | 5403379 |
| 17 | 45323015 |
| 18 | 413310514 |
| 19 | 458633529 |
| 20 | 1789211101 |
| 21 | 2247844630 |
| 22 | 6284900361 |
| 23 | 184509955099 |
| 24 | 375304810559 |
| 25 | 559814765658 |
| 26 | 2054749107533 |
| 27 | 2614563873191 |
| 28 | 25585823966252 |
[1,1,3,4,7,137,555,2912,18027,38966,95959,230884, 326843,884570,1211413,2095983,5403379,45323015, 413310514,458633529,1789211101,2247844630, 6284900361,184509955099,375304810559,559814765658, 2054749107533,2614563873191,25585823966252] |