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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 153 |
| 5 | 1209 |
| 6 | 12285 |
| 7 | 140589 |
| 8 | 1871217 |
| 9 | 27773361 |
| 10 | 460041525 |
| 11 | 8363802501 |
| 12 | 166064229513 |
| 13 | 3570030632169 |
| 14 | 82674532955565 |
| 15 | 2051044762727709 |
| 16 | 54279654050034657 |
| 17 | 1526205561241263201 |
| 18 | 45438086217150617445 |
| 19 | 1427921718081647393781 |
| 20 | 47235337785416646609273 |
[1,1,5,21,153,1209,12285,140589,1871217,27773361, 460041525,8363802501,166064229513,3570030632169, 82674532955565,2051044762727709,54279654050034657, 1526205561241263201,45438086217150617445, 1427921718081647393781,47235337785416646609273] |