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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 45 |
| 5 | 2775 |
| 6 | 239778 |
| 7 | 3293461 |
| 8 | 3815703 |
| 9 | 8142176137578 |
| 10 | 25025955346953 |
| 11 | 27262684236385 |
| 12 | 2430563686654005 |
| 13 | 17543349622599580 |
| 14 | 95966329187365806 |
| 15 | 69152680331115315990 |
| 16 | 130831703828369011153 |
| 17 | 10553338813847920825078 |
| 18 | 120456843371021570368956 |
[1,3,6,45,2775,239778,3293461,3815703, 8142176137578,25025955346953,27262684236385, 2430563686654005,17543349622599580, 95966329187365806,69152680331115315990, 130831703828369011153,10553338813847920825078, 120456843371021570368956] |