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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 24 |
| 5 | 82 |
| 6 | 272 |
| 7 | 908 |
| 8 | 3076 |
| 9 | 10444 |
| 10 | 35480 |
| 11 | 120648 |
| 12 | 410432 |
| 13 | 1396424 |
| 14 | 4751472 |
| 15 | 16168096 |
| 16 | 55017104 |
| 17 | 187214896 |
| 18 | 637067040 |
| 19 | 2167858112 |
| 20 | 7376953152 |
| 21 | 25102872672 |
| 22 | 85422038784 |
| 23 | 290680899264 |
| 24 | 989152113472 |
| 25 | 3365965684288 |
| 26 | 11453976585344 |
[1,4,8,24,82,272,908,3076,10444,35480,120648, 410432,1396424,4751472,16168096,55017104, 187214896,637067040,2167858112,7376953152, 25102872672,85422038784,290680899264,989152113472, 3365965684288,11453976585344] |