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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 13 |
| 4 | 31 |
| 5 | 72 |
| 6 | 169 |
| 7 | 397 |
| 8 | 934 |
| 9 | 2197 |
| 10 | 5166 |
| 11 | 12147 |
| 12 | 28561 |
| 13 | 67156 |
| 14 | 157907 |
| 15 | 371293 |
| 16 | 873034 |
| 17 | 2052795 |
| 18 | 4826809 |
| 19 | 11349443 |
| 20 | 26686340 |
| 21 | 62748517 |
| 22 | 147542765 |
| 23 | 346922420 |
| 24 | 815730721 |
| 25 | 1918055940 |
| 26 | 4509991465 |
| 27 | 10604499373 |
| 28 | 24934727222 |
| 29 | 58629889045 |
[1,2,6,13,31,72,169,397,934,2197,5166,12147,28561, 67156,157907,371293,873034,2052795,4826809, 11349443,26686340,62748517,147542765,346922420, 815730721,1918055940,4509991465,10604499373, 24934727222,58629889045] |