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 | 3 |
| 2 | 14 |
| 3 | 82 |
| 4 | 576 |
| 5 | 4688 |
| 6 | 43264 |
| 7 | 445632 |
| 8 | 5062016 |
| 9 | 62812288 |
| 10 | 844863744 |
| 11 | 12239474432 |
| 12 | 189939644416 |
| 13 | 3142842052608 |
| 14 | 55223903596544 |
| 15 | 1026805938614272 |
| 16 | 20139224002953216 |
| 17 | 415503046091767808 |
| 18 | 8994794537935765504 |
| 19 | 203848794955954716672 |
| 20 | 4826475681472562855936 |
| 21 | 119162892472107134353408 |