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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 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 19 |
| 6 | 50 |
| 7 | 165 |
| 8 | 476 |
| 9 | 1543 |
| 10 | 4544 |
| 11 | 14108 |
| 12 | 41666 |
| 13 | 127313 |
| 14 | 379674 |
| 15 | 1152233 |
| 16 | 3448844 |
| 17 | 10424890 |
| 18 | 31290646 |
| 19 | 94453041 |
| 20 | 284071264 |
| 21 | 857114281 |
| 22 | 2581411140 |
| 23 | 7789677889 |
| 24 | 23486717204 |
| 25 | 70901078303 |
| 26 | 213968862304 |
| 27 | 646246694302 |
[0,0,1,4,19,50,165,476,1543,4544,14108,41666, 127313,379674,1152233,3448844,10424890,31290646, 94453041,284071264,857114281,2581411140, 7789677889,23486717204,70901078303,213968862304, 646246694302] |