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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 36 |
| 5 | 110 |
| 6 | 362 |
| 7 | 1156 |
| 8 | 3858 |
| 9 | 13140 |
| 10 | 44538 |
| 11 | 154572 |
| 12 | 533950 |
| 13 | 1864942 |
| 14 | 6586844 |
| 15 | 23228542 |
| 16 | 82703466 |
| 17 | 294399864 |
| 18 | 1052887478 |
| 19 | 3788424618 |
| 20 | 13629870990 |
| 21 | 49277518878 |
| 22 | 178247528092 |
| 23 | 646510370750 |
| 24 | 2353411404768 |
| 25 | 8569401009866 |
| 26 | 31296013344902 |
| 27 | 114356658125070 |
| 28 | 418622898126256 |
| 29 | 1536077086892826 |
[1,2,4,12,36,110,362,1156,3858,13140,44538,154572, 533950,1864942,6586844,23228542,82703466, 294399864,1052887478,3788424618,13629870990, 49277518878,178247528092,646510370750, 2353411404768,8569401009866,31296013344902, 114356658125070,418622898126256,1536077086892826] |