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 | 15 |
| 3 | 55 |
| 4 | 171 |
| 5 | 1711 |
| 6 | 5151 |
| 7 | 11175 |
| 8 | 551775 |
| 9 | 1777555 |
| 10 | 17555775 |
| 11 | 51151555 |
| 12 | 115117551 |
| 13 | 1115171151 |
| 14 | 151577151715 |
| 15 | 171115717515 |
| 16 | 551171777775 |
| 17 | 1175175575155 |
| 18 | 1577775175717755 |
| 19 | 5511171777517575 |
| 20 | 7571117555155155 |
| 21 | 517577151571517115 |
| 22 | 757171775575551115 |