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) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 42 |
| 5 | 300 |
| 6 | 2475 |
| 7 | 22050 |
| 8 | 220500 |
| 9 | 2381400 |
| 10 | 28279125 |
| 11 | 360186750 |
| 12 | 4970577150 |
| 13 | 73045872900 |
| 14 | 1150472498175 |
| 15 | 19174541636250 |
| 16 | 339663308985000 |
| 17 | 6333077180430000 |
| 18 | 124682456989715625 |
| 19 | 2572020969902133750 |