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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 152 |
| 4 | 1700 |
| 5 | 13932 |
| 6 | 85830 |
| 7 | 420638 |
| 8 | 1716899 |
| 9 | 6040894 |
| 10 | 18802523 |
| 11 | 52809868 |
| 12 | 135947198 |
| 13 | 324787256 |
| 14 | 727441548 |
| 15 | 1540202274 |
| 16 | 3104066741 |
| 17 | 5989089818 |
| 18 | 11116712473 |
| 19 | 19932794912 |
| 20 | 34647071560 |
| 21 | 58558172324 |
| 22 | 96487250498 |
| 23 | 155347652550 |
| 24 | 244882989111 |
| 25 | 378611450006 |
| 26 | 575020279367 |
| 27 | 859061019988 |
| 28 | 1264003479362 |
[1,2,13,152,1700,13932,85830,420638,1716899, 6040894,18802523,52809868,135947198,324787256, 727441548,1540202274,3104066741,5989089818, 11116712473,19932794912,34647071560,58558172324, 96487250498,155347652550,244882989111, 378611450006,575020279367,859061019988, 1264003479362] |