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 | 9 |
| 5 | 1 |
| 6 | 84 |
| 7 | 405 |
| 8 | 81 |
| 9 | 1 |
| 10 | 17550 |
| 11 | 121500 |
| 12 | 32805 |
| 13 | 729 |
| 14 | 1 |
| 15 | 25621596 |
| 16 | 247203171 |
| 17 | 82255257 |
| 18 | 2539107 |
| 19 | 6561 |
| 20 | 1 |
| 21 | 268715232324 |
| 22 | 3543210805275 |
| 23 | 1382411964132 |
| 24 | 53628242751 |
| 25 | 199290375 |
| 26 | 59049 |
| 27 | 1 |
| 28 | 21091830512086620 |
| 29 | 373203783345533355 |