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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 10 |
| 2 | 38 |
| 3 | 158 |
| 4 | 714 |
| 5 | 3378 |
| 6 | 16366 |
| 7 | 80326 |
| 8 | 397202 |
| 9 | 1972826 |
| 10 | 9824694 |
| 11 | 49005294 |
| 12 | 244672090 |
| 13 | 1222297474 |
| 14 | 6108298622 |
| 15 | 30531927062 |
| 16 | 152630937378 |
| 17 | 763068593322 |
| 18 | 3815084686150 |
| 19 | 19074648589630 |
| 20 | 95370918425066 |
| 21 | 476847618556370 |
[2,10,38,158,714,3378,16366,80326,397202,1972826, 9824694,49005294,244672090,1222297474,6108298622, 30531927062,152630937378,763068593322, 3815084686150,19074648589630,95370918425066, 476847618556370] |