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 | 2 |
| 2 | 4 |
| 3 | 28 |
| 4 | 96 |
| 5 | 472 |
| 6 | 1904 |
| 7 | 8528 |
| 8 | 36096 |
| 9 | 157472 |
| 10 | 675904 |
| 11 | 2926528 |
| 12 | 12612096 |
| 13 | 54489472 |
| 14 | 235099904 |
| 15 | 1015094528 |
| 16 | 4381188096 |
| 17 | 18913321472 |
| 18 | 81638523904 |
| 19 | 352410262528 |
| 20 | 1521205764096 |
| 21 | 6566514153472 |
| 22 | 28345085947904 |
| 23 | 122355313430528 |
| 24 | 528161486340096 |