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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 25 |
| 5 | 88 |
| 6 | 311 |
| 7 | 1095 |
| 8 | 3858 |
| 9 | 13591 |
| 10 | 47881 |
| 11 | 168688 |
| 12 | 594289 |
| 13 | 2093693 |
| 14 | 7376120 |
| 15 | 25986209 |
| 16 | 91549913 |
| 17 | 322532092 |
| 18 | 1136286727 |
| 19 | 4003159847 |
| 20 | 14103208628 |
| 21 | 49685873471 |
| 22 | 175044281583 |
| 23 | 616684348614 |
| 24 | 2172590743211 |
| 25 | 7654078700221 |
| 26 | 26965465508072 |
| 27 | 94999850216565 |
[1,2,7,25,88,311,1095,3858,13591,47881,168688, 594289,2093693,7376120,25986209,91549913, 322532092,1136286727,4003159847,14103208628, 49685873471,175044281583,616684348614, 2172590743211,7654078700221,26965465508072, 94999850216565] |