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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 106 |
| 4 | 986 |
| 5 | 9898 |
| 6 | 104535 |
| 7 | 1144630 |
| 8 | 12876908 |
| 9 | 147937396 |
| 10 | 1728352171 |
| 11 | 20471245898 |
| 12 | 245254954252 |
| 13 | 2966792716710 |
| 14 | 36186910210761 |
| 15 | 444559817944096 |
| 16 | 5495828249436652 |
| 17 | 68318636646858588 |
| 18 | 853455362282694440 |
| 19 | 10708603125245767280 |
| 20 | 134897492549870974674 |
[1,2,13,106,986,9898,104535,1144630,12876908, 147937396,1728352171,20471245898,245254954252, 2966792716710,36186910210761,444559817944096, 5495828249436652,68318636646858588, 853455362282694440,10708603125245767280, 134897492549870974674] |