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 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 47 |
| 5 | 244 |
| 6 | 1186 |
| 7 | 5536 |
| 8 | 25147 |
| 9 | 112028 |
| 10 | 491870 |
| 11 | 2135440 |
| 12 | 9188406 |
| 13 | 39249768 |
| 14 | 166656772 |
| 15 | 704069248 |
| 16 | 2961699667 |
| 17 | 12412521388 |
| 18 | 51854046982 |
| 19 | 216013684528 |
| 20 | 897632738722 |
| 21 | 3721813363288 |
| 22 | 15401045060572 |
| 23 | 63616796642368 |
| 24 | 262357557683422 |
| 25 | 1080387930269464 |
| 26 | 4443100381114156 |