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 | 1 |
| 1 | 20 |
| 2 | 420 |
| 3 | 9296 |
| 4 | 216868 |
| 5 | 5313360 |
| 6 | 135866640 |
| 7 | 3599688000 |
| 8 | 98122746660 |
| 9 | 2735243498960 |
| 10 | 77595234251920 |
| 11 | 2231860533960000 |
| 12 | 64904359322352400 |
| 13 | 1904342118510144320 |
| 14 | 56285527873777258560 |
| 15 | 1673824975976543421696 |
| 16 | 50036226313229526706980 |
| 17 | 1502471400349641645458640 |