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 | 15 |
| 4 | 159 |
| 5 | 3903 |
| 6 | 214143 |
| 7 | 25098495 |
| 8 | 6110517759 |
| 9 | 3040867308543 |
| 10 | 3064498377754623 |
| 11 | 6220489664197758975 |
| 12 | 25354161321592779612159 |
| 13 | 207142125428402158677213183 |
| 14 | 3388838467537660347660899221503 |