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 | 12 |
| 2 | 119 |
| 3 | 1175 |
| 4 | 12154 |
| 5 | 133938 |
| 6 | 1580508 |
| 7 | 19978308 |
| 8 | 270074016 |
| 9 | 3894932448 |
| 10 | 59760168192 |
| 11 | 972751628160 |
| 12 | 16752851775360 |
| 13 | 304473528961920 |
| 14 | 5825460745532160 |
| 15 | 117070467915075840 |
| 16 | 2465958106403712000 |
| 17 | 54336917746726272000 |
| 18 | 1250216389189281024000 |