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 | 2 |
| 3 | 12 |
| 4 | 100 |
| 5 | 1080 |
| 6 | 14406 |
| 7 | 229376 |
| 8 | 4251528 |
| 9 | 90000000 |
| 10 | 2143588810 |
| 11 | 56757583872 |
| 12 | 1654301902188 |
| 13 | 52644347205632 |
| 14 | 1816448730468750 |
| 15 | 67553994410557440 |
| 16 | 2694045224950414864 |
| 17 | 114692890480116793344 |
| 18 | 5191945444217181018258 |
| 19 | 249036800000000000000000 |
| 20 | 12617615847934310595791220 |