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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 9 |
| 3 | 75 |
| 4 | 372 |
| 5 | 1725 |
| 6 | 7293 |
| 7 | 29665 |
| 8 | 116539 |
| 9 | 442210 |
| 10 | 1649985 |
| 11 | 6023148 |
| 12 | 21692828 |
| 13 | 77107557 |
| 14 | 271088870 |
| 15 | 944377886 |
| 16 | 3262534584 |
| 17 | 11190762816 |
| 18 | 38140286571 |
| 19 | 129245999168 |
| 20 | 435739937780 |
| 21 | 1462231704463 |
| 22 | 4886245700669 |
| 23 | 16265366134625 |
[0,9,75,372,1725,7293,29665,116539,442210,1649985, 6023148,21692828,77107557,271088870,944377886, 3262534584,11190762816,38140286571,129245999168, 435739937780,1462231704463,4886245700669, 16265366134625] |