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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 103 |
| 4 | 885 |
| 5 | 9051 |
| 6 | 106843 |
| 7 | 1425495 |
| 8 | 21166953 |
| 9 | 345678355 |
| 10 | 6150501831 |
| 11 | 118313311623 |
| 12 | 2444917863325 |
| 13 | 53982840948843 |
| 14 | 1267645359117075 |
| 15 | 31531781398100791 |
| 16 | 827910838693667793 |
| 17 | 22874802838645217955 |
| 18 | 663243613324249850623 |
| 19 | 20130710499843811837095 |
[1,3,15,103,885,9051,106843,1425495,21166953, 345678355,6150501831,118313311623,2444917863325, 53982840948843,1267645359117075,31531781398100791, 827910838693667793,22874802838645217955, 663243613324249850623,20130710499843811837095] |