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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 11 |
| 4 | 27 |
| 5 | 61 |
| 6 | 140 |
| 7 | 327 |
| 8 | 761 |
| 9 | 1769 |
| 10 | 4112 |
| 11 | 9559 |
| 12 | 22222 |
| 13 | 51660 |
| 14 | 120095 |
| 15 | 279187 |
| 16 | 649031 |
| 17 | 1508814 |
| 18 | 3507567 |
| 19 | 8154104 |
| 20 | 18955992 |
| 21 | 44067335 |
| 22 | 102444125 |
| 23 | 238153697 |
| 24 | 553640176 |
| 25 | 1287057259 |
| 26 | 2992045122 |
| 27 | 6955661024 |
| 28 | 16169950087 |
| 29 | 37590573335 |
[1,2,4,11,27,61,140,327,761,1769,4112,9559,22222, 51660,120095,279187,649031,1508814,3507567, 8154104,18955992,44067335,102444125,238153697, 553640176,1287057259,2992045122,6955661024, 16169950087,37590573335] |