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| n | a(n) |
|---|---|
| -1 | 1 |
| 0 | 42 |
| 1 | 783 |
| 2 | 8672 |
| 3 | 65367 |
| 4 | 371520 |
| 5 | 1741655 |
| 6 | 7161696 |
| 7 | 26567946 |
| 8 | 90521472 |
| 9 | 288078201 |
| 10 | 864924480 |
| 11 | 2469235686 |
| 12 | 6748494912 |
| 13 | 17746495281 |
| 14 | 45086909440 |
| 15 | 111066966315 |
| 16 | 266057139456 |
| 17 | 621284327856 |
| 18 | 1417338712800 |
| 19 | 3164665156308 |
[1,42,783,8672,65367,371520,1741655,7161696, 26567946,90521472,288078201,864924480,2469235686, 6748494912,17746495281,45086909440,111066966315, 266057139456,621284327856,1417338712800, 3164665156308] |