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| n | a(n) |
|---|---|
| 1 | 320 |
| 2 | 1660 |
| 3 | 8588 |
| 4 | 45996 |
| 5 | 242644 |
| 6 | 1279474 |
| 7 | 6740992 |
| 8 | 36117846 |
| 9 | 190631336 |
| 10 | 1005363146 |
| 11 | 5297587660 |
| 12 | 28385155912 |
| 13 | 149821450268 |
| 14 | 790147365438 |
| 15 | 4163579409000 |
| 16 | 22309054217762 |
| 17 | 117750984236192 |
| 18 | 621010645500502 |
[320,1660,8588,45996,242644,1279474,6740992, 36117846,190631336,1005363146,5297587660, 28385155912,149821450268,790147365438, 4163579409000,22309054217762,117750984236192, 621010645500502] |