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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 3 |
| 2 | 9 |
| 3 | 32 |
| 4 | 139 |
| 5 | 669 |
| 6 | 3430 |
| 7 | 18360 |
| 8 | 101403 |
| 9 | 573551 |
| 10 | 3305445 |
| 11 | 19340100 |
| 12 | 114579348 |
| 13 | 685962172 |
| 14 | 4143459504 |
| 15 | 25220816752 |
| 16 | 154545611355 |
| 17 | 952583230899 |
| 18 | 5902090839715 |
| 19 | 36738469359480 |
| 20 | 229636903762035 |
| 21 | 1440759023752125 |
| 22 | 9070230371741490 |
| 23 | 57278432955350880 |
[0,3,9,32,139,669,3430,18360,101403,573551, 3305445,19340100,114579348,685962172,4143459504, 25220816752,154545611355,952583230899, 5902090839715,36738469359480,229636903762035, 1440759023752125,9070230371741490, 57278432955350880] |