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) |
|---|---|
| 3 | 1 |
| 4 | 45 |
| 5 | 1350 |
| 6 | 33750 |
| 7 | 759375 |
| 8 | 15946875 |
| 9 | 318937500 |
| 10 | 6150937500 |
| 11 | 115330078125 |
| 12 | 2114384765625 |
| 13 | 38058925781250 |
| 14 | 674680957031250 |
| 15 | 11806916748046875 |
| 16 | 204350482177734375 |
| 17 | 3503151123046875000 |
| 18 | 59553569091796875000 |