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 | 1 |
| 4 | 4 |
| 5 | 16 |
| 6 | 85 |
| 7 | 533 |
| 8 | 3888 |
| 9 | 32268 |
| 10 | 300193 |
| 11 | 3093377 |
| 12 | 34970468 |
| 13 | 430293488 |
| 14 | 5724411845 |
| 15 | 81871668773 |
| 16 | 1252691817856 |
| 17 | 20417647146396 |
| 18 | 353169795861921 |
| 19 | 6461418976274657 |
| 20 | 124664729763630436 |