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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 153 |
| 6 | 873 |
| 7 | 5913 |
| 8 | 46233 |
| 9 | 409113 |
| 10 | 4037913 |
| 11 | 43954713 |
| 12 | 522956313 |
| 13 | 6749977113 |
| 14 | 93928268313 |
| 15 | 1401602636313 |
| 16 | 22324392524313 |
| 17 | 378011820620313 |
| 18 | 6780385526348313 |
| 19 | 128425485935180313 |
| 20 | 2561327494111820313 |
| 21 | 53652269665821260313 |
| 22 | 1177652997443428940313 |
[0,1,3,9,33,153,873,5913,46233,409113,4037913, 43954713,522956313,6749977113,93928268313, 1401602636313,22324392524313,378011820620313, 6780385526348313,128425485935180313, 2561327494111820313,53652269665821260313, 1177652997443428940313] |