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 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 24 |
| 7 | 66 |
| 8 | 178 |
| 9 | 512 |
| 10 | 1486 |
| 11 | 4446 |
| 12 | 13468 |
| 13 | 41648 |
| 14 | 130178 |
| 15 | 412670 |
| 16 | 1321418 |
| 17 | 4274970 |
| 18 | 13948966 |
| 19 | 45890440 |
| 20 | 152061154 |
| 21 | 507292698 |
| 22 | 1702753462 |
| 23 | 5748085332 |
| 24 | 19506240462 |