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 | 12 |
| 2 | 196 |
| 3 | 3120 |
| 4 | 50020 |
| 5 | 799536 |
| 6 | 12799632 |
| 7 | 204724416 |
| 8 | 3276326820 |
| 9 | 52413049520 |
| 10 | 838703348496 |
| 11 | 13418125153472 |
| 12 | 214703825630736 |
| 13 | 3435088134123200 |
| 14 | 54963617747611200 |
| 15 | 879389273444524800 |
| 16 | 14070604335190692900 |
| 17 | 225124668703739770800 |
| 18 | 3602061930346132909200 |