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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 37 |
| 2 | 666 |
| 3 | 7770 |
| 4 | 66045 |
| 5 | 435897 |
| 6 | 2324784 |
| 7 | 10295472 |
| 8 | 38608020 |
| 9 | 124403620 |
| 10 | 348330136 |
| 11 | 854992152 |
| 12 | 1852482996 |
| 13 | 3562467300 |
| 14 | 6107086800 |
| 15 | 9364199760 |
| 16 | 12875774670 |
| 17 | 15905368710 |
| 18 | 17672631900 |
| 19 | 17672631900 |
| 20 | 15905368710 |
| 21 | 12875774670 |
| 22 | 9364199760 |
| 23 | 6107086800 |
[1,37,666,7770,66045,435897,2324784,10295472, 38608020,124403620,348330136,854992152,1852482996, 3562467300,6107086800,9364199760,12875774670, 15905368710,17672631900,17672631900,15905368710, 12875774670,9364199760,6107086800] |