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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 4 |
| 7 | 6 |
| 8 | 26 |
| 9 | 74 |
| 10 | 356 |
| 11 | 1655 |
| 12 | 9750 |
| 13 | 62009 |
| 14 | 448498 |
| 15 | 3554505 |
| 16 | 31000909 |
| 17 | 294772655 |
| 18 | 3047952802 |
| 19 | 34135465140 |