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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 53 |
| 4 | 169 |
| 5 | 473 |
| 6 | 1225 |
| 7 | 3017 |
| 8 | 7177 |
| 9 | 16649 |
| 10 | 37897 |
| 11 | 85001 |
| 12 | 188425 |
| 13 | 413705 |
| 14 | 901129 |
| 15 | 1949705 |
| 16 | 4194313 |
| 17 | 8978441 |
| 18 | 19136521 |
| 19 | 40632329 |
| 20 | 85983241 |
| 21 | 181403657 |
| 22 | 381681673 |
| 23 | 801112073 |
| 24 | 1677721609 |
| 25 | 3506438153 |
| 26 | 7314866185 |
| 27 | 15233712137 |
| 28 | 31675383817 |
| 29 | 65766686729 |
[1,2,13,53,169,473,1225,3017,7177,16649,37897, 85001,188425,413705,901129,1949705,4194313, 8978441,19136521,40632329,85983241,181403657, 381681673,801112073,1677721609,3506438153, 7314866185,15233712137,31675383817,65766686729] |