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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 66 |
| 4 | 412 |
| 5 | 2630 |
| 6 | 17029 |
| 7 | 111344 |
| 8 | 733202 |
| 9 | 4854062 |
| 10 | 32269865 |
| 11 | 215245074 |
| 12 | 1439609582 |
| 13 | 9650033224 |
| 14 | 64808040028 |
| 15 | 435935055728 |
| 16 | 2936358225450 |
| 17 | 19802076360062 |
| 18 | 133678410354017 |
| 19 | 903246297123430 |
| 20 | 6108010982206984 |
| 21 | 41333625143684982 |
| 22 | 279888021880711789 |
[1,2,11,66,412,2630,17029,111344,733202,4854062, 32269865,215245074,1439609582,9650033224, 64808040028,435935055728,2936358225450, 19802076360062,133678410354017,903246297123430, 6108010982206984,41333625143684982, 279888021880711789] |