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 | 3 |
| 2 | 11 |
| 3 | 25 |
| 4 | 274 |
| 5 | 294 |
| 6 | 13068 |
| 7 | 13698 |
| 8 | 114064 |
| 9 | 1062864 |
| 10 | 120543840 |
| 11 | 123870240 |
| 12 | 19802759040 |
| 13 | 20247546240 |
| 14 | 289277533440 |
| 15 | 4420892649600 |
| 16 | 1223405590579200 |
| 17 | 1243166003251200 |
| 18 | 431565146817638400 |
| 19 | 437647401838080000 |