This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 81 |
| 2 | 9801 |
| 3 | 998001 |
| 4 | 99980001 |
| 5 | 9999800001 |
| 6 | 999998000001 |
| 7 | 99999980000001 |
| 8 | 9999999800000001 |
| 9 | 999999998000000001 |
| 10 | 99999999980000000001 |
| 11 | 9999999999800000000001 |
| 12 | 999999999998000000000001 |
| 13 | 99999999999980000000000001 |
| 14 | 9999999999999800000000000001 |
| 15 | 999999999999998000000000000001 |