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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 14 |
| 4 | 42 |
| 5 | 136 |
| 6 | 451 |
| 7 | 1546 |
| 8 | 5407 |
| 9 | 19191 |
| 10 | 69191 |
| 11 | 251867 |
| 12 | 925820 |
| 13 | 3430082 |
| 14 | 12789590 |
| 15 | 47974023 |
| 16 | 180826904 |
| 17 | 684611939 |
| 18 | 2601928569 |
| 19 | 9922514404 |
| 20 | 37956726661 |
| 21 | 145587887723 |
| 22 | 559808213755 |
| 23 | 2157340447787 |
| 24 | 8330424172574 |
| 25 | 32227003874198 |
| 26 | 124881479757620 |
| 27 | 484665714314689 |
| 28 | 1883659790434405 |
[1,2,5,14,42,136,451,1546,5407,19191,69191,251867, 925820,3430082,12789590,47974023,180826904, 684611939,2601928569,9922514404,37956726661, 145587887723,559808213755,2157340447787, 8330424172574,32227003874198,124881479757620, 484665714314689,1883659790434405] |