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 | 5 |
| 2 | 55 |
| 3 | 5005 |
| 4 | 55055 |
| 5 | 50155105 |
| 6 | 5065665605 |
| 7 | 50155155155105 |
| 8 | 5464353998993534645 |
| 9 | 541025148469303964841520145 |
| 10 | 513016415223221833242338122322514610315 |