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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 25 |
| 5 | 239 |
| 6 | 1486 |
| 7 | 7072 |
| 8 | 27828 |
| 9 | 94720 |
| 10 | 287298 |
| 11 | 793024 |
| 12 | 2023332 |
| 13 | 4828941 |
| 14 | 10881820 |
| 15 | 23327332 |
| 16 | 47861324 |
| 17 | 94458120 |
| 18 | 180072500 |
| 19 | 332769135 |
| 20 | 597905471 |
| 21 | 1047219371 |
| 22 | 1791963626 |
| 23 | 3001600740 |
| 24 | 4930040800 |
| 25 | 7951993320 |
| 26 | 12612734550 |
[0,0,1,25,239,1486,7072,27828,94720,287298,793024, 2023332,4828941,10881820,23327332,47861324, 94458120,180072500,332769135,597905471,1047219371, 1791963626,3001600740,4930040800,7951993320, 12612734550] |