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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 28 |
| 5 | 62 |
| 6 | 246 |
| 7 | 657 |
| 8 | 2518 |
| 9 | 7746 |
| 10 | 28610 |
| 11 | 97018 |
| 12 | 351968 |
| 13 | 1267138 |
| 14 | 4608816 |
| 15 | 17111597 |
| 16 | 63199376 |
| 17 | 237990728 |
| 18 | 895931962 |
| 19 | 3401928286 |
| 20 | 13017241734 |
| 21 | 49840610290 |
| 22 | 192867979884 |
| 23 | 745646164078 |
| 24 | 2906679205874 |
| 25 | 11348492247540 |
| 26 | 44491661323862 |
| 27 | 175173809862642 |
| 28 | 690669793705394 |
| 29 | 2736791992802570 |
[1,1,4,7,28,62,246,657,2518,7746,28610,97018, 351968,1267138,4608816,17111597,63199376, 237990728,895931962,3401928286,13017241734, 49840610290,192867979884,745646164078, 2906679205874,11348492247540,44491661323862, 175173809862642,690669793705394,2736791992802570] |