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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 19 |
| 3 | 136 |
| 4 | 714 |
| 5 | 3354 |
| 6 | 14946 |
| 7 | 64664 |
| 8 | 274676 |
| 9 | 1152494 |
| 10 | 4793874 |
| 11 | 19813536 |
| 12 | 81495084 |
| 13 | 333932596 |
| 14 | 1364199604 |
| 15 | 5559496912 |
| 16 | 22610923448 |
| 17 | 91805888342 |
| 18 | 372224952818 |
| 19 | 1507347830672 |
| 20 | 6097720950428 |
| 21 | 24644919356012 |
| 22 | 99527343620348 |
[1,19,136,714,3354,14946,64664,274676,1152494, 4793874,19813536,81495084,333932596,1364199604, 5559496912,22610923448,91805888342,372224952818, 1507347830672,6097720950428,24644919356012, 99527343620348] |