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) |
|---|---|
| 1 | 1 |
| 2 | 31 |
| 3 | 431 |
| 4 | 5431 |
| 5 | 75431 |
| 6 | 1475431 |
| 7 | 91475431 |
| 8 | 691475431 |
| 9 | 57691475431 |
| 10 | 1357691475431 |
| 11 | 181357691475431 |
| 12 | 17181357691475431 |
| 13 | 1617181357691475431 |
| 14 | 121617181357691475431 |
| 15 | 20121617181357691475431 |