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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 6 |
| 5 | 13 |
| 6 | 19 |
| 7 | 24 |
| 8 | 116 |
| 9 | 139 |
| 10 | 6015 |
| 11 | 39112 |
| 12 | 65605 |
| 13 | 94020 |
| 14 | 1566318 |
| 15 | 2446259 |
| 16 | 3226100 |
| 17 | 5897845 |
| 18 | 85155749 |
| 19 | 1628068810 |
| 20 | 4244431852 |
| 21 | 14977877039 |
| 22 | 21118804085 |
| 23 | 110954554736 |
[0,1,4,6,13,19,24,116,139,6015,39112,65605,94020, 1566318,2446259,3226100,5897845,85155749, 1628068810,4244431852,14977877039,21118804085, 110954554736] |