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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 24 |
| 6 | 144 |
| 7 | 504 |
| 8 | 1344 |
| 9 | 3024 |
| 10 | 78624 |
| 11 | 809424 |
| 12 | 4809024 |
| 13 | 20787624 |
| 14 | 72696624 |
| 15 | 1961583624 |
| 16 | 28478346624 |
| 17 | 238536558624 |
| 18 | 1425925698624 |
| 19 | 6764765838624 |
| 20 | 189239120970624 |
| 21 | 3500701266525624 |
| 22 | 37764092547420624 |
| 23 | 288099608198025624 |