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 | 2 |
| 3 | 4 |
| 4 | 24 |
| 5 | 169 |
| 6 | 2024 |
| 7 | 29584 |
| 8 | 525600 |
| 9 | 10764961 |
| 10 | 250030128 |
| 11 | 6484436676 |
| 12 | 185752964096 |
| 13 | 5824523694025 |
| 14 | 198428723433728 |
| 15 | 7298231591777344 |
| 16 | 288230377359679488 |
| 17 | 12165297972404595841 |
| 18 | 546477889989773968640 |
| 19 | 26031837574639154232100 |
| 20 | 1310720000002816000131072 |