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 | 1 |
| 2 | 20 |
| 3 | 399 |
| 4 | 7960 |
| 5 | 158801 |
| 6 | 3168060 |
| 7 | 63202399 |
| 8 | 1260879920 |
| 9 | 25154396001 |
| 10 | 501827040100 |
| 11 | 10011386405999 |
| 12 | 199725901079880 |
| 13 | 3984506635191601 |
| 14 | 79490406802752140 |
| 15 | 1585823629419851199 |
| 16 | 31636982181594271840 |