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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 32 |
| 5 | 132 |
| 6 | 623 |
| 7 | 3314 |
| 8 | 19628 |
| 9 | 128126 |
| 10 | 914005 |
| 11 | 7074517 |
| 12 | 59050739 |
| 13 | 528741491 |
| 14 | 5055414317 |
| 15 | 51406084221 |
| 16 | 553946196892 |
| 17 | 6305737560455 |
| 18 | 75610546284387 |
| 19 | 952559077043183 |
| 20 | 12579235034203780 |
| 21 | 173759983171005721 |
| 22 | 2505751777457313815 |
| 23 | 37657189917162605826 |
[0,1,3,9,32,132,623,3314,19628,128126,914005, 7074517,59050739,528741491,5055414317,51406084221, 553946196892,6305737560455,75610546284387, 952559077043183,12579235034203780, 173759983171005721,2505751777457313815, 37657189917162605826] |