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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 82 |
| 5 | 312 |
| 6 | 1210 |
| 7 | 4752 |
| 8 | 18834 |
| 9 | 75184 |
| 10 | 301856 |
| 11 | 1217604 |
| 12 | 4930626 |
| 13 | 20032052 |
| 14 | 81615072 |
| 15 | 333328532 |
| 16 | 1364264250 |
| 17 | 5594210292 |
| 18 | 22977466864 |
| 19 | 94517423444 |
| 20 | 389316529512 |
| 21 | 1605533230256 |
| 22 | 6628467569292 |
| 23 | 27393187077144 |
| 24 | 113310732332274 |
| 25 | 469101108803052 |
[1,2,6,22,82,312,1210,4752,18834,75184,301856, 1217604,4930626,20032052,81615072,333328532, 1364264250,5594210292,22977466864,94517423444, 389316529512,1605533230256,6628467569292, 27393187077144,113310732332274,469101108803052] |