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 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 0 |
| 6 | 1 |
| 7 | 7 |
| 8 | 1 |
| 9 | 13 |
| 10 | 34 |
| 11 | 20 |
| 12 | 100 |
| 13 | 226 |
| 14 | 234 |
| 15 | 853 |
| 16 | 1877 |
| 17 | 2650 |
| 18 | 8128 |
| 19 | 18116 |
| 20 | 30483 |
| 21 | 85713 |