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 | 1 |
| 2 | 6 |
| 3 | 28 |
| 4 | 90 |
| 5 | 120 |
| 6 | 496 |
| 7 | 672 |
| 8 | 8128 |
| 9 | 10080 |
| 10 | 63700 |
| 11 | 220500 |
| 12 | 523776 |
| 13 | 1323000 |
| 14 | 1528800 |
| 15 | 2056320 |
| 16 | 7856640 |
| 17 | 33550336 |
| 18 | 44553600 |
| 19 | 162729000 |
| 20 | 252927360 |
| 21 | 459818240 |
| 22 | 1379454720 |
| 23 | 1476304896 |
| 24 | 1980840960 |
| 25 | 8589869056 |