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| n | a(n) |
|---|---|
| 1 | 850 |
| 2 | 3880 |
| 3 | 15480 |
| 4 | 43848 |
| 5 | 213120 |
| 6 | 881848 |
| 7 | 2568432 |
| 8 | 12681664 |
| 9 | 53297808 |
| 10 | 157483872 |
| 11 | 782763648 |
| 12 | 3314813344 |
| 13 | 9868152000 |
| 14 | 49199192320 |
| 15 | 209132201280 |
| 16 | 624968085888 |
| 17 | 3120427983360 |
| 18 | 13288964395648 |
| 19 | 39789382386432 |
| 20 | 198807593780224 |
[850,3880,15480,43848,213120,881848,2568432, 12681664,53297808,157483872,782763648,3314813344, 9868152000,49199192320,209132201280,624968085888, 3120427983360,13288964395648,39789382386432, 198807593780224] |