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 | 0 |
| 3 | 0 |
| 4 | 3 |
| 5 | 63 |
| 6 | 865 |
| 7 | 11068 |
| 8 | 133862 |
| 9 | 1563465 |
| 10 | 17836903 |
| 11 | 200051717 |
| 12 | 2214357712 |
| 13 | 24255601105 |
| 14 | 263439785143 |
| 15 | 2841076717752 |
| 16 | 30457549169277 |
| 17 | 324855769153426 |
| 18 | 3449587218984911 |
| 19 | 36489283363168885 |