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 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 71 |
| 5 | 789 |
| 6 | 10365 |
| 7 | 157031 |
| 8 | 2692497 |
| 9 | 51519756 |
| 10 | 1088093185 |
| 11 | 25140587651 |
| 12 | 630820490833 |
| 13 | 17082650998878 |
| 14 | 496596665961713 |
| 15 | 15425333714935513 |
| 16 | 509890407550644949 |
| 17 | 17871584701588777344 |
| 18 | 662057571007292023593 |
| 19 | 25847670560115633381442 |