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 | 0 |
| 2 | 1 |
| 3 | 121 |
| 4 | 6889 |
| 5 | 10201 |
| 6 | 69169 |
| 7 | 1002001 |
| 8 | 5221225 |
| 9 | 100020001 |
| 10 | 109181601 |
| 11 | 522808225 |
| 12 | 602555209 |
| 13 | 10000200001 |
| 14 | 62188888129 |
| 15 | 1000002000001 |
| 16 | 1212225222121 |
| 17 | 100000020000001 |
| 18 | 10000000200000001 |
| 19 | 10022212521222001 |
| 20 | 12102202520220121 |