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 | 1 |
| 3 | 10 |
| 4 | 45 |
| 5 | 351 |
| 6 | 1540 |
| 7 | 11935 |
| 8 | 52326 |
| 9 | 405450 |
| 10 | 1777555 |
| 11 | 13773376 |
| 12 | 60384555 |
| 13 | 467889345 |
| 14 | 2051297326 |
| 15 | 15894464365 |
| 16 | 69683724540 |
| 17 | 539943899076 |
| 18 | 2367195337045 |
| 19 | 18342198104230 |
| 20 | 80414957735001 |
| 21 | 623094791644755 |
| 22 | 2731741367653000 |
| 23 | 21166880717817451 |
| 24 | 92798791542467010 |