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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 28 |
| 5 | 85 |
| 6 | 275 |
| 7 | 910 |
| 8 | 3091 |
| 9 | 10837 |
| 10 | 38949 |
| 11 | 142254 |
| 12 | 526138 |
| 13 | 1971964 |
| 14 | 7491686 |
| 15 | 28773491 |
| 16 | 111407278 |
| 17 | 434643804 |
| 18 | 1709385164 |
| 19 | 6772781723 |
| 20 | 26994738921 |
| 21 | 108149870681 |
| 22 | 435557791070 |
| 23 | 1763296481670 |
| 24 | 7170999317794 |
| 25 | 29276232512536 |
| 26 | 119968051032055 |
| 27 | 493463560033734 |
| 28 | 2036939467083106 |
[1,2,4,10,28,85,275,910,3091,10837,38949,142254, 526138,1971964,7491686,28773491,111407278, 434643804,1709385164,6772781723,26994738921, 108149870681,435557791070,1763296481670, 7170999317794,29276232512536,119968051032055, 493463560033734,2036939467083106] |