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 | 0 |
| 5 | 0 |
| 6 | 15 |
| 7 | 8456 |
| 8 | 954213 |
| 9 | 66253552 |
| 10 | 3622342095 |
| 11 | 172672602432 |
| 12 | 7557346901841 |
| 13 | 312733696544984 |
| 14 | 12456923582109435 |
| 15 | 483124650731622328 |
| 16 | 18383758048494864909 |
| 17 | 689931203330381971296 |
| 18 | 25630900118611348761735 |
| 19 | 945025181750878420241744 |
| 20 | 34647077709586498046291817 |