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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 31 |
| 2 | 930 |
| 3 | 27900 |
| 4 | 837000 |
| 5 | 25110000 |
| 6 | 753300000 |
| 7 | 22599000000 |
| 8 | 677969999535 |
| 9 | 20339099972100 |
| 10 | 610172998744965 |
| 11 | 18305189949807900 |
| 12 | 549155698118005500 |
| 13 | 16474670932253220000 |
| 14 | 494240127628988250000 |
| 15 | 14827203818711397000000 |
[1,31,930,27900,837000,25110000,753300000, 22599000000,677969999535,20339099972100, 610172998744965,18305189949807900, 549155698118005500,16474670932253220000, 494240127628988250000,14827203818711397000000] |