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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 21 |
| 6 | 125 |
| 7 | 825 |
| 8 | 6133 |
| 9 | 49925 |
| 10 | 439417 |
| 11 | 4142945 |
| 12 | 41544161 |
| 13 | 440710117 |
| 14 | 4924691541 |
| 15 | 57766255689 |
| 16 | 709205703565 |
| 17 | 9090541134373 |
| 18 | 121389729560633 |
| 19 | 1685431945085489 |
| 20 | 24289856880005441 |
| 21 | 362776874949660485 |
| 22 | 5606980244843123077 |
| 23 | 89560387072919814553 |