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 | 5050 |
| 3 | 25200 |
| 4 | 255255 |
| 5 | 500500 |
| 6 | 50005000 |
| 7 | 525220255 |
| 8 | 2250500505 |
| 9 | 5000050000 |
| 10 | 22052205055 |
| 11 | 500000500000 |
| 12 | 520022025225 |
| 13 | 2205022050055 |
| 14 | 2225205025200 |
| 15 | 5220005220550 |
| 16 | 50000005000000 |
| 17 | 220500220500055 |
| 18 | 550250022200005 |
| 19 | 2552552000225055 |
| 20 | 5000000050000000 |