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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 10 |
| 6 | 67 |
| 7 | 380 |
| 8 | 1978 |
| 9 | 9814 |
| 10 | 47391 |
| 11 | 225590 |
| 12 | 1067527 |
| 13 | 5051454 |
| 14 | 24001979 |
| 15 | 114858924 |
| 16 | 554704282 |
| 17 | 2707092726 |
| 18 | 13359365962 |
| 19 | 66678605418 |
| 20 | 336519708452 |
| 21 | 1716476383658 |
| 22 | 8842304168692 |
| 23 | 45966748864706 |
| 24 | 240938394287134 |
| 25 | 1272300373503706 |
[1,10,67,380,1978,9814,47391,225590,1067527, 5051454,24001979,114858924,554704282,2707092726, 13359365962,66678605418,336519708452, 1716476383658,8842304168692,45966748864706, 240938394287134,1272300373503706] |