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 | 15 |
| 3 | 945 |
| 4 | 175 |
| 5 | 17325 |
| 6 | 23648625 |
| 7 | 1576575 |
| 8 | 7309575 |
| 9 | 1283268987 |
| 10 | 3360942585 |
| 11 | 1932541986375 |
| 12 | 135664447443525 |
| 13 | 218461268025 |
| 14 | 242856109621125 |
| 15 | 27604644460267875 |
| 16 | 4479480941961650625 |
| 17 | 1151866527932995875 |
| 18 | 31580724596338947904875 |
| 19 | 809762169136896100125 |
| 20 | 4742892704944677157875 |