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| n | a(n) |
|---|---|
| 1 | 312 |
| 2 | 1668 |
| 3 | 8764 |
| 4 | 44668 |
| 5 | 224948 |
| 6 | 1181206 |
| 7 | 6170564 |
| 8 | 31538382 |
| 9 | 160690160 |
| 10 | 838194016 |
| 11 | 4355102280 |
| 12 | 22315658240 |
| 13 | 114413801424 |
| 14 | 594413227190 |
| 15 | 3078427346856 |
| 16 | 15808430494646 |
| 17 | 81314611678564 |
| 18 | 421380982769344 |
| 19 | 2178294253001920 |
[312,1668,8764,44668,224948,1181206,6170564, 31538382,160690160,838194016,4355102280, 22315658240,114413801424,594413227190, 3078427346856,15808430494646,81314611678564, 421380982769344,2178294253001920] |