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Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 14 |
| 5 | 64 |
| 6 | 426 |
| 7 | 2790 |
| 8 | 24024 |
| 9 | 205056 |
| 10 | 2170680 |
| 11 | 22852200 |
| 12 | 287250480 |
| 13 | 3597143040 |
| 14 | 52370755920 |
| 15 | 760381337520 |
| 16 | 12585067447680 |
| 17 | 207863095910400 |
| 18 | 3854801333416320 |
| 19 | 71370457471716480 |
| 20 | 1465957162768492800 |
| 21 | 30071395843421184000 |
| 22 | 677696237345719468800 |
[1,0,1,3,14,64,426,2790,24024,205056,2170680, 22852200,287250480,3597143040,52370755920, 760381337520,12585067447680,207863095910400, 3854801333416320,71370457471716480, 1465957162768492800,30071395843421184000, 677696237345719468800] |