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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 15 |
| 3 | 74 |
| 4 | 411 |
| 5 | 2447 |
| 6 | 16386 |
| 7 | 117207 |
| 8 | 879908 |
| 9 | 6849047 |
| 10 | 54818296 |
| 11 | 448725003 |
| 12 | 3741217498 |
[0,15,74,411,2447,16386,117207,879908,6849047, 54818296,448725003,3741217498] |