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 | 18 |
| 4 | 160 |
| 5 | 2325 |
| 6 | 41895 |
| 7 | 961772 |
| 8 | 26978400 |
| 9 | 929587995 |
| 10 | 36843728625 |
| 11 | 1705290814194 |
| 12 | 89802671542272 |
| 13 | 5336424046419557 |
| 14 | 354379732734283200 |
| 15 | 26173529641406219400 |