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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 15 |
| 6 | 155 |
| 7 | 1400 |
| 8 | 11991 |
| 9 | 101031 |
| 10 | 853315 |
| 11 | 7300260 |
| 12 | 63641006 |
| 13 | 567304452 |
| 14 | 5181338526 |
| 15 | 48538121450 |
| 16 | 466611951261 |
| 17 | 4603782469653 |
| 18 | 46613101232933 |
| 19 | 484188586821376 |
| 20 | 5157850655391981 |
| 21 | 56321812548867229 |
| 22 | 630125374420189131 |
| 23 | 7219368394888423554 |
| 24 | 84658119388335562972 |
[1,15,155,1400,11991,101031,853315,7300260, 63641006,567304452,5181338526,48538121450, 466611951261,4603782469653,46613101232933, 484188586821376,5157850655391981, 56321812548867229,630125374420189131, 7219368394888423554,84658119388335562972] |