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 | 2 |
| 2 | 20 |
| 3 | 130 |
| 4 | 4000 |
| 5 | 34385 |
| 6 | 127658 |
| 7 | 154375 |
| 8 | 338143 |
| 9 | 1462240 |
| 10 | 22936888 |
| 11 | 104087491 |
| 12 | 756449941 |
| 13 | 1252467550 |
| 14 | 3953591108800 |
| 15 | 110329835126080 |
| 16 | 112834800815577880 |
| 17 | 149099873130116779 |
| 18 | 26141903882328110417 |