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 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 23 |
| 6 | 47 |
| 7 | 139 |
| 8 | 283 |
| 9 | 659 |
| 10 | 1319 |
| 11 | 8637 |
| 12 | 20147 |
| 13 | 83491 |
| 14 | 169861 |
| 15 | 999013 |
| 16 | 3797401 |
| 17 | 8153567 |
| 18 | 55443959 |
| 19 | 187814447 |
| 20 | 646611887 |