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 | 28 |
| 3 | 168 |
| 4 | 1854 |
| 5 | 19776 |
| 6 | 327152 |
| 7 | 1244416 |
| 8 | 27319968 |
| 9 | 178422816 |
| 10 | 22222222056 |
| 11 | 2075415810048 |
| 12 | 308768621226000 |
| 13 | 12455031810211128 |
| 14 | 2469135782022242640 |
| 15 | 197530862561779410288 |
| 16 | 21604938101329359719880 |
| 17 | 1821571286217135606177024 |
| 18 | 270250398197557076360997936 |