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 | 3 |
| 3 | 195 |
| 4 | 5145 |
| 5 | 504945 |
| 6 | 47896695 |
| 7 | 4900634739 |
| 8 | 432180333585 |
| 9 | 57753467156385 |
| 10 | 8322385282168815 |
| 11 | 1297830988347128235 |
| 12 | 195029484510994774641 |
| 13 | 36350420770495795788825 |
| 14 | 7233322663694914389377775 |
| 15 | 1534057832485607065840824075 |