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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 7 |
| 5 | 14 |
| 6 | 49 |
| 7 | 1156 |
| 8 | 2531 |
| 9 | 2461 |
| 10 | 5263 |
| 11 | 23231 |
| 12 | 48857 |
| 13 | 142327 |
| 14 | 161366 |
| 15 | 677983151 |
| 16 | 701098187 |
| 17 | 49162215523 |
| 18 | 56895744916 |
| 19 | 97659246406291 |
| 20 | 28593399072431 |
| 21 | 21502630803250973 |
| 22 | 26851741349945933 |
| 23 | 246602936364321931 |
| 24 | 1508124176077531039 |
| 25 | 10968493811640186469 |