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 | 24 |
| 3 | 285 |
| 4 | 4242 |
| 5 | 73206 |
| 6 | 1403028 |
| 7 | 29082339 |
| 8 | 640672890 |
| 9 | 14818136190 |
| 10 | 356665411440 |
| 11 | 8874875097270 |
| 12 | 227135946200940 |
| 13 | 5955171596514900 |
| 14 | 159439898653636320 |
| 15 | 4347741997166750235 |
| 16 | 120493374240909299130 |
| 17 | 3387806231071627372590 |
| 18 | 96488484001399878973200 |