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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 6 |
| 3 | 10 |
| 4 | 36 |
| 5 | 94 |
| 6 | 274 |
| 7 | 768 |
| 8 | 2182 |
| 9 | 6170 |
| 10 | 17476 |
| 11 | 49470 |
| 12 | 140066 |
| 13 | 396544 |
| 14 | 1122694 |
| 15 | 3178538 |
| 16 | 8999012 |
| 17 | 25477790 |
| 18 | 72132146 |
| 19 | 204218880 |
| 20 | 578179846 |
| 21 | 1636929594 |
| 22 | 4634437764 |
| 23 | 13120914558 |
| 24 | 37147634242 |
| 25 | 105171535360 |
| 26 | 297759253766 |
[0,6,10,36,94,274,768,2182,6170,17476,49470, 140066,396544,1122694,3178538,8999012,25477790, 72132146,204218880,578179846,1636929594, 4634437764,13120914558,37147634242,105171535360, 297759253766] |