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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 99 |
| 5 | 408 |
| 6 | 1743 |
| 7 | 7592 |
| 8 | 33719 |
| 9 | 151442 |
| 10 | 687913 |
| 11 | 3151179 |
| 12 | 14538075 |
| 13 | 67481244 |
| 14 | 314877361 |
| 15 | 1475843667 |
| 16 | 6945055325 |
| 17 | 32796434702 |
| 18 | 155356830111 |
| 19 | 737985256349 |
| 20 | 3514444677653 |
| 21 | 16774687944748 |
| 22 | 80233031911899 |
| 23 | 384480428069964 |
| 24 | 1845654312853857 |
| 25 | 8874050298857830 |
| 26 | 42730272114282057 |
| 27 | 206036821996122797 |
[1,2,7,25,99,408,1743,7592,33719,151442,687913, 3151179,14538075,67481244,314877361,1475843667, 6945055325,32796434702,155356830111,737985256349, 3514444677653,16774687944748,80233031911899, 384480428069964,1845654312853857,8874050298857830, 42730272114282057,206036821996122797] |