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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 52 |
| 5 | 370 |
| 6 | 1620 |
| 7 | 5285 |
| 8 | 14168 |
| 9 | 33012 |
| 10 | 69240 |
| 11 | 133815 |
| 12 | 242220 |
| 13 | 415558 |
| 14 | 681772 |
| 15 | 1076985 |
| 16 | 1646960 |
| 17 | 2448680 |
| 18 | 3552048 |
| 19 | 5041707 |
| 20 | 7018980 |
| 21 | 9603930 |
| 22 | 12937540 |
| 23 | 17184013 |
| 24 | 22533192 |
| 25 | 29203100 |
| 26 | 37442600 |
| 27 | 47534175 |
| 28 | 59796828 |
| 29 | 74589102 |
| 30 | 92312220 |
| 31 | 113413345 |
| 32 | 138388960 |
[0,0,3,52,370,1620,5285,14168,33012,69240,133815, 242220,415558,681772,1076985,1646960,2448680, 3552048,5041707,7018980,9603930,12937540,17184013, 22533192,29203100,37442600,47534175,59796828, 74589102,92312220,113413345,138388960] |