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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 11 |
| 6 | 33 |
| 7 | 91 |
| 8 | 342 |
| 9 | 1305 |
| 10 | 5940 |
| 11 | 28227 |
| 12 | 144545 |
| 13 | 760109 |
| 14 | 4112455 |
| 15 | 22571026 |
| 16 | 125410006 |
| 17 | 702370207 |
| 18 | 3959138462 |
| 19 | 22425417823 |
| 20 | 127530807883 |
| 21 | 727630240442 |
| 22 | 4163114784625 |
| 23 | 23876534534361 |
| 24 | 137228556011456 |
| 25 | 790200525479694 |
| 26 | 4557943660168122 |
| 27 | 26331300028827092 |
[1,1,1,2,5,11,33,91,342,1305,5940,28227,144545, 760109,4112455,22571026,125410006,702370207, 3959138462,22425417823,127530807883,727630240442, 4163114784625,23876534534361,137228556011456, 790200525479694,4557943660168122, 26331300028827092] |