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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 8 |
| 2 | 34 |
| 3 | 152 |
| 4 | 706 |
| 5 | 3368 |
| 6 | 16354 |
| 7 | 80312 |
| 8 | 397186 |
| 9 | 1972808 |
| 10 | 9824674 |
| 11 | 49005272 |
| 12 | 244672066 |
| 13 | 1222297448 |
| 14 | 6108298594 |
| 15 | 30531927032 |
| 16 | 152630937346 |
| 17 | 763068593288 |
| 18 | 3815084686114 |
| 19 | 19074648589592 |
| 20 | 95370918425026 |
| 21 | 476847618556328 |
[2,8,34,152,706,3368,16354,80312,397186,1972808, 9824674,49005272,244672066,1222297448,6108298594, 30531927032,152630937346,763068593288, 3815084686114,19074648589592,95370918425026, 476847618556328] |