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 | 337 |
| 6 | 8733 |
| 7 | 96478 |
| 8 | 668028 |
| 9 | 3413828 |
| 10 | 14054915 |
| 11 | 49171641 |
| 12 | 151422970 |
| 13 | 420674150 |
| 14 | 1073422309 |
| 15 | 2550004472 |
| 16 | 5699074284 |
| 17 | 12082541388 |
| 18 | 24462528078 |
| 19 | 47555986746 |
| 20 | 89173692795 |
| 21 | 161899772067 |
| 22 | 285517344145 |
| 23 | 490447009030 |