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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 23 |
| 4 | 65 |
| 5 | 186 |
| 6 | 529 |
| 7 | 1504 |
| 8 | 4278 |
| 9 | 12167 |
| 10 | 34601 |
| 11 | 98402 |
| 12 | 279841 |
| 13 | 795831 |
| 14 | 2263236 |
| 15 | 6436343 |
| 16 | 18304103 |
| 17 | 52054435 |
| 18 | 148035889 |
| 19 | 420994377 |
| 20 | 1197252006 |
| 21 | 3404825447 |
| 22 | 9682870661 |
| 23 | 27536796143 |
| 24 | 78310985281 |
| 25 | 222706025200 |
| 26 | 633346311281 |
| 27 | 1801152661463 |
| 28 | 5122238579606 |
[1,3,8,23,65,186,529,1504,4278,12167,34601,98402, 279841,795831,2263236,6436343,18304103,52054435, 148035889,420994377,1197252006,3404825447, 9682870661,27536796143,78310985281,222706025200, 633346311281,1801152661463,5122238579606] |