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 | 2 |
| 1 | 5 |
| 2 | 41 |
| 3 | 364 |
| 4 | 4294 |
| 5 | 57882 |
| 6 | 888440 |
| 7 | 15120105 |
| 8 | 281942218 |
| 9 | 5698630860 |
| 10 | 123850400282 |
| 11 | 2875187314622 |
| 12 | 70909556575040 |
| 13 | 1849319825544900 |
| 14 | 50801676938400207 |
| 15 | 1464954360561398340 |
| 16 | 44213852151914127210 |
| 17 | 1392971702129279452950 |
| 18 | 45705100441643456206404 |
| 19 | 1558551328538087579977710 |