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| n | a(n) |
|---|---|
| 2 | 2 |
| 3 | 21 |
| 4 | 364 |
| 5 | 8855 |
| 6 | 278256 |
| 7 | 10737573 |
| 8 | 491796152 |
| 9 | 26088783435 |
| 10 | 1573664496040 |
| 11 | 106395830418878 |
| 12 | 7970714909592876 |
| 13 | 655454164338881388 |
| 14 | 58702034425556612832 |
| 15 | 5687847988198592380965 |
| 16 | 592867741295430227919600 |
[2,21,364,8855,278256,10737573,491796152, 26088783435,1573664496040,106395830418878, 7970714909592876,655454164338881388, 58702034425556612832,5687847988198592380965, 592867741295430227919600] |