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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 4 |
| 2 | 5 |
| 3 | 20 |
| 4 | 20 |
| 5 | 113 |
| 6 | 113 |
| 7 | 781 |
| 8 | 781 |
| 9 | 5953 |
| 10 | 5953 |
| 11 | 47995 |
| 12 | 47995 |
| 13 | 401696 |
| 14 | 401696 |
| 15 | 3438339 |
| 16 | 3438339 |
| 17 | 30483565 |
| 18 | 30483565 |
| 19 | 269577430 |
| 20 | 269577430 |
| 21 | 2427668363 |
| 22 | 2427668363 |
| 23 | 22170468927 |
| 24 | 22170468927 |
| 25 | 202985860292 |
| 26 | 202985860292 |
[0,4,5,20,20,113,113,781,781,5953,5953,47995, 47995,401696,401696,3438339,3438339,30483565, 30483565,269577430,269577430,2427668363, 2427668363,22170468927,22170468927,202985860292, 202985860292] |