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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 11 |
| 4 | 47 |
| 5 | 143 |
| 6 | 555 |
| 7 | 1981 |
| 8 | 7477 |
| 9 | 28549 |
| 10 | 108961 |
| 11 | 426105 |
| 12 | 1662133 |
| 13 | 6568089 |
| 14 | 26088533 |
| 15 | 104028671 |
| 16 | 418100919 |
| 17 | 1683005799 |
| 18 | 6816895227 |
| 19 | 27676678867 |
| 20 | 112793176879 |
| 21 | 461118216915 |
| 22 | 1889680551359 |
| 23 | 7767367649263 |
| 24 | 31991637007963 |
| 25 | 132086685745455 |
| 26 | 546431369722467 |
| 27 | 2264882999794055 |
[1,1,5,11,47,143,555,1981,7477,28549,108961, 426105,1662133,6568089,26088533,104028671, 418100919,1683005799,6816895227,27676678867, 112793176879,461118216915,1889680551359, 7767367649263,31991637007963,132086685745455, 546431369722467,2264882999794055] |