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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 44 |
| 3 | 242 |
| 4 | 1376 |
| 5 | 8018 |
| 6 | 47384 |
| 7 | 282122 |
| 8 | 1686176 |
| 9 | 10097378 |
| 10 | 60525224 |
| 11 | 362974202 |
| 12 | 2177313776 |
| 13 | 13062288338 |
| 14 | 78368947064 |
| 15 | 470199333482 |
| 16 | 2821152954176 |
| 17 | 16926788584898 |
| 18 | 101560344088904 |
| 19 | 609360902271962 |
| 20 | 3656161926847376 |
[1,8,44,242,1376,8018,47384,282122,1686176, 10097378,60525224,362974202,2177313776, 13062288338,78368947064,470199333482, 2821152954176,16926788584898,101560344088904, 609360902271962,3656161926847376] |