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 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 18 |
| 5 | 48 |
| 6 | 360 |
| 7 | 450 |
| 8 | 6174 |
| 9 | 27000 |
| 10 | 34200 |
| 11 | 93250 |
| 12 | 1776566 |
| 13 | 11293824 |
| 14 | 172014648 |
| 15 | 1296688778 |
| 16 | 20393895570 |
| 17 | 173895132784 |
| 18 | 3328106382492 |
| 19 | 11622794050422 |
| 20 | 287786755919610 |
| 21 | 709366149217940 |
| 22 | 17019652496034468 |
| 23 | 198351459813601270 |