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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 26 |
| 4 | 129 |
| 5 | 477 |
| 6 | 1393 |
| 7 | 3504 |
| 8 | 7939 |
| 9 | 16557 |
| 10 | 32164 |
| 11 | 59007 |
| 12 | 102948 |
| 13 | 172648 |
| 14 | 279310 |
| 15 | 438095 |
| 16 | 668822 |
| 17 | 996738 |
| 18 | 1453619 |
| 19 | 2079775 |
| 20 | 2923564 |
| 21 | 4045784 |
| 22 | 5518395 |
| 23 | 7428549 |
| 24 | 9879866 |
| 25 | 12994062 |
| 26 | 16914082 |
| 27 | 21807830 |
| 28 | 27866722 |
| 29 | 35315990 |
| 30 | 44410161 |
| 31 | 55442069 |
[1,4,26,129,477,1393,3504,7939,16557,32164,59007, 102948,172648,279310,438095,668822,996738,1453619, 2079775,2923564,4045784,5518395,7428549,9879866, 12994062,16914082,21807830,27866722,35315990, 44410161,55442069] |