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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 112 |
| 4 | 1392 |
| 5 | 21472 |
| 6 | 394752 |
| 7 | 8421632 |
| 8 | 204525312 |
| 9 | 5572091392 |
| 10 | 168331164672 |
| 11 | 5585571889152 |
| 12 | 201973854584832 |
| 13 | 7905697598963712 |
| 14 | 333049899230625792 |
| 15 | 15025907115679875072 |
| 16 | 722841343143300759552 |
| 17 | 36935846945562562527232 |
| 18 | 1997902532753538016346112 |
| 19 | 114050521905958855289864192 |
| 20 | 6852141240070150728132329472 |
[1,2,12,112,1392,21472,394752,8421632,204525312, 5572091392,168331164672,5585571889152, 201973854584832,7905697598963712, 333049899230625792,15025907115679875072, 722841343143300759552,36935846945562562527232, 1997902532753538016346112, 114050521905958855289864192, 6852141240070150728132329472] |