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 | 3 |
| 2 | 20 |
| 3 | 78 |
| 4 | 352 |
| 5 | 1365 |
| 6 | 5232 |
| 7 | 18271 |
| 8 | 60598 |
| 9 | 187296 |
| 10 | 548020 |
| 11 | 1515265 |
| 12 | 3991204 |
| 13 | 10035401 |
| 14 | 24210308 |
| 15 | 56188768 |
| 16 | 125904351 |
| 17 | 273044682 |
| 18 | 574635828 |
| 19 | 1176027747 |
| 20 | 2345376048 |
| 21 | 4565886531 |
| 22 | 8691118644 |
| 23 | 16198834634 |
| 24 | 29602895824 |
| 25 | 53105875363 |