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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 90 |
| 6 | 346 |
| 7 | 1268 |
| 8 | 5042 |
| 9 | 19996 |
| 10 | 81938 |
| 11 | 339484 |
| 12 | 1430989 |
| 13 | 6091398 |
| 14 | 26262618 |
| 15 | 114062647 |
| 16 | 500199764 |
| 17 | 2207452156 |
| 18 | 9810250085 |
| 19 | 43847809271 |
| 20 | 197025418977 |
| 21 | 889648032464 |
| 22 | 4034769757042 |
| 23 | 18372808349124 |
| 24 | 83978227766573 |
| 25 | 385153726452491 |
| 26 | 1772156467187142 |
| 27 | 8178011190408715 |
| 28 | 37843702730012539 |
[1,1,3,8,28,90,346,1268,5042,19996,81938,339484, 1430989,6091398,26262618,114062647,500199764, 2207452156,9810250085,43847809271,197025418977, 889648032464,4034769757042,18372808349124, 83978227766573,385153726452491,1772156467187142, 8178011190408715,37843702730012539] |