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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 37 |
| 6 | 177 |
| 7 | 959 |
| 8 | 6097 |
| 9 | 41641 |
| 10 | 325249 |
| 11 | 2693691 |
| 12 | 24807321 |
| 13 | 241586893 |
| 14 | 2558036145 |
| 15 | 28607094455 |
| 16 | 342232522657 |
| 17 | 4315903789009 |
| 18 | 57569080467073 |
| 19 | 807258131578995 |
| 20 | 11879658510739497 |
| 21 | 183184249105857781 |
| 22 | 2948163649552594737 |
| 23 | 49548882107764546223 |
[1,1,1,3,9,37,177,959,6097,41641,325249,2693691, 24807321,241586893,2558036145,28607094455, 342232522657,4315903789009,57569080467073, 807258131578995,11879658510739497, 183184249105857781,2948163649552594737, 49548882107764546223] |