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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 71 |
| 4 | 918 |
| 5 | 6667 |
| 6 | 33665 |
| 7 | 131616 |
| 8 | 425866 |
| 9 | 1192178 |
| 10 | 2977857 |
| 11 | 6785605 |
| 12 | 14339006 |
| 13 | 28451061 |
| 14 | 53519713 |
| 15 | 96176822 |
| 16 | 166119570 |
| 17 | 277155796 |
| 18 | 448497281 |
| 19 | 706337523 |
| 20 | 1085753062 |
| 21 | 1632969935 |
| 22 | 2408039361 |
| 23 | 3487969276 |
| 24 | 4970360858 |
| 25 | 6977601702 |
| 26 | 9661669825 |
| 27 | 13209605201 |
| 28 | 17849708046 |
[1,71,918,6667,33665,131616,425866,1192178, 2977857,6785605,14339006,28451061,53519713, 96176822,166119570,277155796,448497281,706337523, 1085753062,1632969935,2408039361,3487969276, 4970360858,6977601702,9661669825,13209605201, 17849708046] |