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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 4 |
| 4 | 35 |
| 5 | 87 |
| 6 | 496 |
| 7 | 1335 |
| 8 | 7552 |
| 9 | 21382 |
| 10 | 122942 |
| 11 | 348597 |
| 12 | 2045395 |
| 13 | 5812073 |
| 14 | 34558802 |
| 15 | 98272393 |
| 16 | 589386556 |
| 17 | 1678849694 |
| 18 | 10123122248 |
| 19 | 28893573238 |
| 20 | 174842616458 |
| 21 | 500084523708 |
| 22 | 3033764103592 |
| 23 | 8694157659203 |
| 24 | 52844583851218 |
| 25 | 151707321284408 |
[0,4,4,35,87,496,1335,7552,21382,122942,348597, 2045395,5812073,34558802,98272393,589386556, 1678849694,10123122248,28893573238,174842616458, 500084523708,3033764103592,8694157659203, 52844583851218,151707321284408] |