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 | 3 |
| 3 | 7 |
| 4 | 27 |
| 5 | 127 |
| 6 | 747 |
| 7 | 5167 |
| 8 | 41067 |
| 9 | 368047 |
| 10 | 3669867 |
| 11 | 40284847 |
| 12 | 482671467 |
| 13 | 6267305647 |
| 14 | 87660962667 |
| 15 | 1313941673647 |
| 16 | 21010450850667 |
| 17 | 357001369769647 |
| 18 | 6423384156578667 |
| 19 | 122002101778601647 |
| 20 | 2439325392333218667 |