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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 24 |
| 4 | 86 |
| 5 | 348 |
| 6 | 1478 |
| 7 | 6324 |
| 8 | 26846 |
| 9 | 112668 |
| 10 | 467798 |
| 11 | 1925124 |
| 12 | 7867406 |
| 13 | 31980588 |
| 14 | 129475718 |
| 15 | 522603924 |
| 16 | 2104600766 |
| 17 | 8461122108 |
| 18 | 33972973238 |
| 19 | 136278002724 |
| 20 | 546271650926 |
[1,3,8,24,86,348,1478,6324,26846,112668,467798, 1925124,7867406,31980588,129475718,522603924, 2104600766,8461122108,33972973238,136278002724, 546271650926] |