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 | 500500 |
| 4 | 50005000 |
| 5 | 5000050000 |
| 6 | 500000500000 |
| 7 | 558080805855 |
| 8 | 50000005000000 |
| 9 | 808505508008850 |
| 10 | 5000000050000000 |
| 11 | 500000000500000000 |
| 12 | 50000000005000000000 |
| 13 | 5000000000050000000000 |
| 14 | 5055055888880005805800 |
| 15 | 500000000000500000000000 |