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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 10 |
| 6 | 34 |
| 7 | 112 |
| 8 | 398 |
| 9 | 1443 |
| 10 | 5387 |
| 11 | 20482 |
| 12 | 79177 |
| 13 | 310102 |
| 14 | 1228187 |
| 15 | 4910413 |
| 16 | 19792582 |
| 17 | 80343445 |
| 18 | 328159601 |
| 19 | 1347699906 |
| 20 | 5561774999 |
| 21 | 23052871229 |
| 22 | 95926831442 |
| 23 | 400587408251 |
| 24 | 1678251696379 |
| 25 | 7051768702245 |
| 26 | 29710764875014 |