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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 88 |
| 3 | 672 |
| 4 | 5168 |
| 5 | 39796 |
| 6 | 306520 |
| 7 | 2361008 |
| 8 | 18186104 |
| 9 | 140082072 |
| 10 | 1079010248 |
| 11 | 8311293248 |
| 12 | 64019406944 |
| 13 | 493122351856 |
| 14 | 3798374049312 |
| 15 | 29257739717488 |
| 16 | 225363621979872 |
| 17 | 1735908604096736 |
| 18 | 13371185000068864 |
| 19 | 102994240528644064 |
[1,12,88,672,5168,39796,306520,2361008,18186104, 140082072,1079010248,8311293248,64019406944, 493122351856,3798374049312,29257739717488, 225363621979872,1735908604096736, 13371185000068864,102994240528644064] |