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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 | 21 |
| 4 | 123 |
| 5 | 531 |
| 6 | 2547 |
| 7 | 11745 |
| 8 | 54957 |
| 9 | 255753 |
| 10 | 1192623 |
| 11 | 5557191 |
| 12 | 25901847 |
| 13 | 120714693 |
| 14 | 562609041 |
| 15 | 2622085629 |
| 16 | 12220512675 |
| 17 | 56954899323 |
| 18 | 265444104699 |
| 19 | 1237128910377 |
| 20 | 5765764156725 |
| 21 | 26871924749169 |
| 22 | 125239314486231 |
[0,9,21,123,531,2547,11745,54957,255753,1192623, 5557191,25901847,120714693,562609041,2622085629, 12220512675,56954899323,265444104699, 1237128910377,5765764156725,26871924749169, 125239314486231] |