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 | 8 |
| 2 | 52 |
| 3 | 264 |
| 4 | 1194 |
| 5 | 4872 |
| 6 | 18516 |
| 7 | 66264 |
| 8 | 226083 |
| 9 | 740608 |
| 10 | 2344232 |
| 11 | 7202416 |
| 12 | 21562164 |
| 13 | 63090288 |
| 14 | 180884088 |
| 15 | 509245776 |
| 16 | 1410356133 |
| 17 | 3848340312 |
| 18 | 10359516684 |
| 19 | 27544099704 |
| 20 | 72406891326 |
| 21 | 188356187448 |