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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 6 |
| 3 | 26 |
| 4 | 206 |
| 5 | 1100 |
| 6 | 7314 |
| 7 | 42920 |
| 8 | 274010 |
| 9 | 1677332 |
| 10 | 10616070 |
| 11 | 66290046 |
| 12 | 419754586 |
| 13 | 2648500908 |
| 14 | 16818685050 |
| 15 | 106781976774 |
| 16 | 680250643910 |
| 17 | 4337083126232 |
| 18 | 27709045093274 |
| 19 | 177213890858938 |
| 20 | 1135003956744310 |
| 21 | 7276652578220372 |
| 22 | 46702733068082702 |
| 23 | 300013046145979184 |
[0,6,26,206,1100,7314,42920,274010,1677332, 10616070,66290046,419754586,2648500908, 16818685050,106781976774,680250643910, 4337083126232,27709045093274,177213890858938, 1135003956744310,7276652578220372, 46702733068082702,300013046145979184] |