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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 25 |
| 4 | 66 |
| 5 | 168 |
| 6 | 417 |
| 7 | 1014 |
| 8 | 2427 |
| 9 | 5737 |
| 10 | 13412 |
| 11 | 31088 |
| 12 | 71506 |
| 13 | 163378 |
| 14 | 371272 |
| 15 | 839248 |
| 16 | 1889019 |
| 17 | 4235082 |
| 18 | 9459687 |
| 19 | 21067566 |
| 20 | 46769977 |
| 21 | 103574916 |
| 22 | 228808544 |
| 23 | 504286803 |
| 24 | 1109344029 |
| 25 | 2435398781 |
| 26 | 5337497418 |
| 27 | 11678931098 |
[1,3,9,25,66,168,417,1014,2427,5737,13412,31088, 71506,163378,371272,839248,1889019,4235082, 9459687,21067566,46769977,103574916,228808544, 504286803,1109344029,2435398781,5337497418, 11678931098] |