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 | 55 |
| 2 | 99 |
| 3 | 5050 |
| 4 | 7272 |
| 5 | 7777 |
| 6 | 9999 |
| 7 | 500500 |
| 8 | 648648 |
| 9 | 851851 |
| 10 | 999999 |
| 11 | 13641364 |
| 12 | 24752475 |
| 13 | 25252525 |
| 14 | 36363636 |
| 15 | 50005000 |
| 16 | 61116111 |
| 17 | 88888888 |
| 18 | 99999999 |
| 19 | 1111111111 |
| 20 | 3888938889 |
| 21 | 4132841328 |
| 22 | 5000050000 |
| 23 | 5243952439 |
| 24 | 9756097560 |
| 25 | 9999999999 |
| 26 | 159341159341 |
| 27 | 175676175676 |
| 28 | 233415233415 |