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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 250 |
| 6 | 480916 |
| 7 | 54916456 |
| 8 | 1962132800 |
| 9 | 34690541994 |
| 10 | 385983794500 |
| 11 | 3095143575007 |
| 12 | 19437996015280 |
| 13 | 100963195651565 |
| 14 | 450398154002132 |
| 15 | 1773257833600750 |
| 16 | 6288010190509312 |
| 17 | 20398342362118678 |
| 18 | 61282868654684052 |
| 19 | 172190699515632837 |
| 20 | 456120623076014000 |