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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 30 |
| 6 | 94 |
| 7 | 299 |
| 8 | 991 |
| 9 | 3390 |
| 10 | 11925 |
| 11 | 42865 |
| 12 | 156975 |
| 13 | 583406 |
| 14 | 2199907 |
| 15 | 8397070 |
| 16 | 32397041 |
| 17 | 126177221 |
| 18 | 495665601 |
| 19 | 1962310738 |
| 20 | 7823383494 |
| 21 | 31389093385 |
| 22 | 126675590877 |
| 23 | 513964543645 |
| 24 | 2095629993499 |
| 25 | 8583643133905 |
| 26 | 35306927076883 |
| 27 | 145797956023790 |
| 28 | 604269114905701 |
| 29 | 2512993929528821 |
[1,1,2,4,11,30,94,299,991,3390,11925,42865,156975, 583406,2199907,8397070,32397041,126177221, 495665601,1962310738,7823383494,31389093385, 126675590877,513964543645,2095629993499, 8583643133905,35306927076883,145797956023790, 604269114905701,2512993929528821] |