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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 55 |
| 4 | 577 |
| 5 | 7441 |
| 6 | 113671 |
| 7 | 2003527 |
| 8 | 39971905 |
| 9 | 889608097 |
| 10 | 21834577351 |
| 11 | 585555975511 |
| 12 | 17027451783937 |
| 13 | 533460597334705 |
| 14 | 17908302027585607 |
| 15 | 641152804988733031 |
| 16 | 24380543011087797121 |
| 17 | 981149507717921468737 |
| 18 | 41653436572936172408455 |
| 19 | 1860174362332664149119607 |
[1,1,7,55,577,7441,113671,2003527,39971905, 889608097,21834577351,585555975511,17027451783937, 533460597334705,17908302027585607, 641152804988733031,24380543011087797121, 981149507717921468737,41653436572936172408455, 1860174362332664149119607] |