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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 16 |
| 3 | 170 |
| 4 | 1696 |
| 5 | 15962 |
| 6 | 144496 |
| 7 | 1273610 |
| 8 | 11012416 |
| 9 | 93864122 |
| 10 | 791266576 |
| 11 | 6612607850 |
| 12 | 54878189536 |
| 13 | 452866803482 |
| 14 | 3719823438256 |
| 15 | 30436810578890 |
| 16 | 248242046141056 |
| 17 | 2019169299698042 |
| 18 | 16385984911571536 |
| 19 | 132716292890482730 |
| 20 | 1073129238309234976 |
| 21 | 8664826172771491802 |
[1,2,16,170,1696,15962,144496,1273610,11012416, 93864122,791266576,6612607850,54878189536, 452866803482,3719823438256,30436810578890, 248242046141056,2019169299698042, 16385984911571536,132716292890482730, 1073129238309234976,8664826172771491802] |