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) |
|---|---|
| 0 | 1 |
| 1 | 11 |
| 2 | 61 |
| 3 | 361 |
| 4 | 2311 |
| 5 | 15401 |
| 6 | 104401 |
| 7 | 712531 |
| 8 | 4875781 |
| 9 | 33398201 |
| 10 | 228859951 |
| 11 | 1568486161 |
| 12 | 10750188961 |
| 13 | 73681909211 |
| 14 | 505020747661 |
| 15 | 3461456968201 |
| 16 | 23725161388951 |
| 17 | 162614629188281 |
| 18 | 1114577128871281 |
| 19 | 7639424974303651 |
| 20 | 52361396909490901 |