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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 61 |
| 4 | 345 |
| 5 | 2085 |
| 6 | 13182 |
| 7 | 86106 |
| 8 | 576543 |
| 9 | 3936029 |
| 10 | 27294390 |
| 11 | 191722887 |
| 12 | 1361291244 |
| 13 | 9754412169 |
| 14 | 70447946556 |
| 15 | 512278417176 |
| 16 | 3747570671685 |
| 17 | 27561220671408 |
| 18 | 203657352324178 |
| 19 | 1511270129552163 |
| 20 | 11257532921742528 |
[1,3,12,61,345,2085,13182,86106,576543,3936029, 27294390,191722887,1361291244,9754412169, 70447946556,512278417176,3747570671685, 27561220671408,203657352324178,1511270129552163, 11257532921742528] |