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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 89 |
| 5 | 377 |
| 6 | 1597 |
| 7 | 6765 |
| 8 | 28657 |
| 9 | 121393 |
| 10 | 514229 |
| 11 | 2178309 |
| 12 | 9227465 |
| 13 | 39088169 |
| 14 | 165580141 |
| 15 | 701408733 |
| 16 | 2971215073 |
| 17 | 12586269025 |
| 18 | 53316291173 |
| 19 | 225851433717 |
| 20 | 956722026041 |
| 21 | 4052739537881 |
| 22 | 17167680177565 |
| 23 | 72723460248141 |
| 24 | 308061521170129 |
| 25 | 1304969544928657 |
| 26 | 5527939700884757 |
[1,1,5,21,89,377,1597,6765,28657,121393,514229, 2178309,9227465,39088169,165580141,701408733, 2971215073,12586269025,53316291173,225851433717, 956722026041,4052739537881,17167680177565, 72723460248141,308061521170129,1304969544928657, 5527939700884757] |