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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 99 |
| 4 | 622 |
| 5 | 3406 |
| 6 | 16399 |
| 7 | 70192 |
| 8 | 272801 |
| 9 | 974066 |
| 10 | 3232454 |
| 11 | 10054552 |
| 12 | 29532523 |
| 13 | 82397798 |
| 14 | 219500791 |
| 15 | 560691234 |
| 16 | 1378470505 |
| 17 | 3272266551 |
| 18 | 7521401992 |
| 19 | 16780966687 |
| 20 | 36420942317 |
| 21 | 77044661996 |
| 22 | 159126985181 |
| 23 | 321388308477 |
[1,13,99,622,3406,16399,70192,272801,974066, 3232454,10054552,29532523,82397798,219500791, 560691234,1378470505,3272266551,7521401992, 16780966687,36420942317,77044661996,159126985181, 321388308477] |