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 | 5151 |
| 5 | 8515 |
| 6 | 581581 |
| 7 | 885115 |
| 8 | 1188111 |
| 9 | 11188815 |
| 10 | 51151555 |
| 11 | 81581151 |
| 12 | 88851115 |
| 13 | 851585815 |
| 14 | 8888511115 |
| 15 | 888885111115 |
| 16 | 88888851111115 |
| 17 | 8888888511111115 |
| 18 | 888888885111111115 |
| 19 | 5885188811851888815 |
| 20 | 15158585181118581555 |
| 21 | 88888888851111111115 |