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 | 3 |
| 4 | 3 |
| 5 | 15 |
| 6 | 9 |
| 7 | 315 |
| 8 | 315 |
| 9 | 567 |
| 10 | 14175 |
| 11 | 6237 |
| 12 | 467775 |
| 13 | 6081075 |
| 14 | 773955 |
| 15 | 638512875 |
| 16 | 9823275 |
| 17 | 10854718875 |
| 18 | 7514805375 |
| 19 | 21837140325 |
| 20 | 9280784638125 |
| 21 | 38979295480125 |
| 22 | 2143861251406875 |
| 23 | 3792985290950625 |
| 24 | 1183411410776595 |
| 25 | 336196423516078125 |
| 26 | 9615217712559834375 |