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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 16 |
| 5 | 30 |
| 6 | 39 |
| 7 | 175 |
| 8 | 784 |
| 9 | 2100 |
| 10 | 4590 |
| 11 | 13970 |
| 12 | 50743 |
| 13 | 153634 |
| 14 | 408499 |
| 15 | 1187823 |
| 16 | 3843280 |
| 17 | 11908160 |
| 18 | 34470084 |
| 19 | 101394222 |
| 20 | 313440606 |
| 21 | 967143586 |
| 22 | 2897603170 |
| 23 | 8660763804 |
| 24 | 26408966551 |
| 25 | 80995131580 |
| 26 | 245801163530 |
| 27 | 742776778965 |
| 28 | 2260469097315 |
| 29 | 6912033833250 |
| 30 | 21074993569539 |
[1,0,0,3,16,30,39,175,784,2100,4590,13970,50743, 153634,408499,1187823,3843280,11908160,34470084, 101394222,313440606,967143586,2897603170, 8660763804,26408966551,80995131580,245801163530, 742776778965,2260469097315,6912033833250, 21074993569539] |