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 | 0 |
| 2 | 24 |
| 3 | 1272 |
| 4 | 27192 |
| 5 | 537720 |
| 6 | 10638648 |
| 7 | 211640184 |
| 8 | 4223114808 |
| 9 | 84382898808 |
| 10 | 1687017131832 |
| 11 | 33735198879096 |
| 12 | 674662776506424 |
| 13 | 13492925768472696 |
| 14 | 269855876817045816 |
| 15 | 5397096426544159608 |
| 16 | 107941759648376656440 |
| 17 | 2158833841895083390584 |
| 18 | 43176666029284877542200 |
| 19 | 863533234116651651590520 |