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Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 9 |
| 3 | 90 |
| 4 | 657 |
| 5 | 4230 |
| 6 | 25533 |
| 7 | 148410 |
| 8 | 842265 |
| 9 | 4704750 |
| 10 | 25994709 |
| 11 | 142528770 |
| 12 | 777216177 |
| 13 | 4221470070 |
| 14 | 22863109293 |
| 15 | 123563792970 |
| 16 | 666766408905 |
| 17 | 3593844532350 |
| 18 | 19354295087109 |
| 19 | 104165322930450 |
| 20 | 560359838547297 |
[0,9,90,657,4230,25533,148410,842265,4704750, 25994709,142528770,777216177,4221470070, 22863109293,123563792970,666766408905, 3593844532350,19354295087109,104165322930450, 560359838547297] |