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 | 2 |
| 4 | 4 |
| 5 | 6 |
| 6 | 18 |
| 7 | 36 |
| 8 | 12 |
| 9 | 30 |
| 10 | 162 |
| 11 | 18 |
| 12 | 330 |
| 13 | 136 |
| 14 | 858 |
| 15 | 1092 |
| 16 | 198 |
| 17 | 1470 |
| 18 | 882 |
| 19 | 9520 |
| 20 | 13260 |
| 21 | 124800 |
| 22 | 1216 |
| 23 | 33966 |
| 24 | 603060 |
| 25 | 27742 |
| 26 | 2141898 |
| 27 | 677586 |