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 | 3 |
| 3 | 13 |
| 4 | 31 |
| 5 | 170 |
| 6 | 804 |
| 7 | 2744 |
| 8 | 12343 |
| 9 | 55657 |
| 10 | 214485 |
| 11 | 923990 |
| 12 | 4008013 |
| 13 | 16241904 |
| 14 | 68963484 |
| 15 | 293830787 |
| 16 | 1216393406 |
| 17 | 5135225641 |
| 18 | 21711233759 |
| 19 | 90692128053 |
| 20 | 381960417890 |
| 21 | 1609647053073 |
| 22 | 6749229887672 |
| 23 | 28396742081001 |
| 24 | 119506154362773 |
| 25 | 501879008939056 |