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 | 7 |
| 2 | 91 |
| 3 | 973 |
| 4 | 9919 |
| 5 | 99757 |
| 6 | 999271 |
| 7 | 9997813 |
| 8 | 99993439 |
| 9 | 999980317 |
| 10 | 9999940951 |
| 11 | 99999822853 |
| 12 | 999999468559 |
| 13 | 9999998405677 |
| 14 | 99999995217031 |
| 15 | 999999985651093 |
| 16 | 9999999956953279 |
| 17 | 99999999870859837 |
| 18 | 999999999612579511 |
| 19 | 9999999998837738533 |
| 20 | 99999999996513215599 |