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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 | 2 |
| 2 | 16 |
| 3 | 110 |
| 4 | 840 |
| 5 | 6502 |
| 6 | 51424 |
| 7 | 411602 |
| 8 | 3326600 |
| 9 | 27082460 |
| 10 | 221776016 |
| 11 | 1824750424 |
| 12 | 15073212648 |
| 13 | 124926064460 |
| 14 | 1038330110400 |
| 15 | 8651387371360 |
| 16 | 72238476287112 |
| 17 | 604327981885262 |
| 18 | 5064140053702240 |
| 19 | 42500097815152940 |
| 20 | 357157266768270840 |
| 21 | 3005093769261481238 |
[1,2,16,110,840,6502,51424,411602,3326600, 27082460,221776016,1824750424,15073212648, 124926064460,1038330110400,8651387371360, 72238476287112,604327981885262,5064140053702240, 42500097815152940,357157266768270840, 3005093769261481238] |