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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 24 |
| 6 | 62 |
| 7 | 156 |
| 8 | 406 |
| 9 | 1040 |
| 10 | 2714 |
| 11 | 7012 |
| 12 | 18322 |
| 13 | 47560 |
| 14 | 124358 |
| 15 | 323708 |
| 16 | 846766 |
| 17 | 2208032 |
| 18 | 5777330 |
| 19 | 15082372 |
| 20 | 39469786 |