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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 32 |
| 3 | 168 |
| 4 | 800 |
| 5 | 3352 |
| 6 | 13616 |
| 7 | 55488 |
| 8 | 223012 |
| 9 | 889328 |
| 10 | 3559604 |
| 11 | 14258048 |
| 12 | 57030476 |
| 13 | 228151816 |
| 14 | 912765036 |
| 15 | 3650768940 |
[1,4,32,168,800,3352,13616,55488,223012,889328, 3559604,14258048,57030476,228151816,912765036, 3650768940] |