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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 16 |
| 3 | 0 |
| 4 | 560 |
| 5 | 384 |
| 6 | 46824 |
| 7 | 253952 |
| 8 | 5141408 |
| 9 | 44013568 |
| 10 | 628801280 |
| 11 | 6441106368 |
| 12 | 81395792936 |
| 13 | 898467518528 |
| 14 | 10813539098984 |
| 15 | 123094927843072 |
| 16 | 1452323503655432 |
| 17 | 16743873126866752 |
| 18 | 195934939996794440 |
| 19 | 2270867565108570304 |
| 20 | 26483057736012701952 |
[1,0,16,0,560,384,46824,253952,5141408,44013568, 628801280,6441106368,81395792936,898467518528, 10813539098984,123094927843072,1452323503655432, 16743873126866752,195934939996794440, 2270867565108570304,26483057736012701952] |