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 | 1 |
| 4 | 3 |
| 5 | 10 |
| 6 | 51 |
| 7 | 319 |
| 8 | 2311 |
| 9 | 19061 |
| 10 | 176311 |
| 11 | 1807182 |
| 12 | 20330789 |
| 13 | 249052162 |
| 14 | 3299941146 |
| 15 | 47024161318 |
| 16 | 717118460091 |
| 17 | 11653174976469 |
| 18 | 201017268344079 |
| 19 | 3668565147279424 |
| 20 | 70619879085128904 |
| 21 | 1430052551473860293 |