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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 5 |
| 5 | 17 |
| 6 | 32 |
| 7 | 97 |
| 8 | 225 |
| 9 | 628 |
| 10 | 1573 |
| 11 | 4225 |
| 12 | 10880 |
| 13 | 28769 |
| 14 | 74849 |
| 15 | 196708 |
| 16 | 513765 |
| 17 | 1347025 |
| 18 | 3523360 |
| 19 | 9229441 |
| 20 | 24154625 |
| 21 | 63251156 |
| 22 | 165571781 |
| 23 | 433507969 |
| 24 | 1134881280 |
| 25 | 2971250497 |
| 26 | 7778684737 |
| 27 | 20365103812 |
| 28 | 53316141125 |
| 29 | 139584105233 |
| 30 | 365434903328 |
| 31 | 956722661665 |
[1,1,4,5,17,32,97,225,628,1573,4225,10880,28769, 74849,196708,513765,1347025,3523360,9229441, 24154625,63251156,165571781,433507969,1134881280, 2971250497,7778684737,20365103812,53316141125, 139584105233,365434903328,956722661665] |