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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 35 |
| 4 | 154 |
| 5 | 637 |
| 6 | 2548 |
| 7 | 9996 |
| 8 | 38759 |
| 9 | 149205 |
| 10 | 571781 |
| 11 | 2184910 |
| 12 | 8333871 |
| 13 | 31750824 |
| 14 | 120875944 |
| 15 | 459957169 |
| 16 | 1749692735 |
| 17 | 6654580387 |
| 18 | 25306064602 |
| 19 | 96226175941 |
| 20 | 365880389868 |
| 21 | 1391138718116 |
| 22 | 5289228800247 |
| 23 | 20109822277181 |
| 24 | 76457523763621 |
| 25 | 290689756066542 |
[0,1,7,35,154,637,2548,9996,38759,149205,571781, 2184910,8333871,31750824,120875944,459957169, 1749692735,6654580387,25306064602,96226175941, 365880389868,1391138718116,5289228800247, 20109822277181,76457523763621,290689756066542] |