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 | 4 |
| 2 | 25 |
| 3 | 205 |
| 4 | 2065 |
| 5 | 24601 |
| 6 | 337837 |
| 7 | 5249581 |
| 8 | 91006657 |
| 9 | 1740663937 |
| 10 | 36402220141 |
| 11 | 826159146253 |
| 12 | 20220201899377 |
| 13 | 530828186303377 |
| 14 | 14878044338021677 |
| 15 | 443397290411503021 |
| 16 | 14000282854007503105 |
| 17 | 466866129420834410881 |
| 18 | 16395362179348570608205 |
| 19 | 604794784980600986425645 |