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 | 36 |
| 2 | 1260 |
| 3 | 44100 |
| 4 | 1543500 |
| 5 | 54022500 |
| 6 | 1890787500 |
| 7 | 66177562500 |
| 8 | 2316214687500 |
| 9 | 81067514061870 |
| 10 | 2837362992143400 |
| 11 | 99307704724247880 |
| 12 | 3475769665321686600 |
| 13 | 121651938285314409000 |
| 14 | 4257817839952942545000 |
| 15 | 149023624397195827125000 |