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 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 25 |
| 5 | 121 |
| 6 | 361 |
| 7 | 5881 |
| 8 | 82321 |
| 9 | 547345 |
| 10 | 6053041 |
| 11 | 167991121 |
| 12 | 2179469161 |
| 13 | 22892967241 |
| 14 | 788375451865 |
| 15 | 18046198202761 |
| 16 | 245523704069281 |
| 17 | 7548055281543841 |
| 18 | 270833271588545761 |
| 19 | 5369819950838359585 |
| 20 | 141456920470310708281 |
| 21 | 6760255576117937586841 |