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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 7 |
| 3 | 16 |
| 4 | 53 |
| 5 | 154 |
| 6 | 436 |
| 7 | 1268 |
| 8 | 3660 |
| 9 | 10610 |
| 10 | 30744 |
| 11 | 89079 |
| 12 | 258251 |
| 13 | 748420 |
| 14 | 2169219 |
| 15 | 6287336 |
| 16 | 18222901 |
| 17 | 52817261 |
| 18 | 153084840 |
| 19 | 443698814 |
| 20 | 1286012537 |
| 21 | 3727362387 |
| 22 | 10803344089 |
| 23 | 31312289784 |
| 24 | 90755170545 |
| 25 | 263043739916 |
| 26 | 762402920030 |
| 27 | 2209739758798 |
| 28 | 6404684091893 |
[2,7,16,53,154,436,1268,3660,10610,30744,89079, 258251,748420,2169219,6287336,18222901,52817261, 153084840,443698814,1286012537,3727362387, 10803344089,31312289784,90755170545,263043739916, 762402920030,2209739758798,6404684091893] |