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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 44 |
| 5 | 143 |
| 6 | 611 |
| 7 | 2163 |
| 8 | 9630 |
| 9 | 35865 |
| 10 | 163797 |
| 11 | 633361 |
| 12 | 2935662 |
| 13 | 11687995 |
| 14 | 54690772 |
| 15 | 222657047 |
| 16 | 1049628640 |
| 17 | 4346023981 |
| 18 | 20619536561 |
| 19 | 86505774633 |
| 20 | 412674097142 |
| 21 | 1750096851891 |
| 22 | 8385970602390 |
| 23 | 35894112184155 |
| 24 | 172605375658844 |
| 25 | 744745093072759 |
| 26 | 3591762156155667 |
| 27 | 15605322676581161 |
[1,1,4,11,44,143,611,2163,9630,35865,163797, 633361,2935662,11687995,54690772,222657047, 1049628640,4346023981,20619536561,86505774633, 412674097142,1750096851891,8385970602390, 35894112184155,172605375658844,744745093072759, 3591762156155667,15605322676581161] |