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 | 24 |
| 4 | 720 |
| 5 | 6300 |
| 6 | 34812 |
| 7 | 135552 |
| 8 | 436944 |
| 9 | 1198968 |
| 10 | 2929656 |
| 11 | 6516984 |
| 12 | 13502448 |
| 13 | 26208516 |
| 14 | 48407988 |
| 15 | 85481280 |
| 16 | 145200888 |
| 17 | 238502808 |
| 18 | 380729160 |
| 19 | 591761304 |
| 20 | 899049096 |
| 21 | 1336994100 |
| 22 | 1950873276 |
| 23 | 2798226336 |
| 24 | 3952174032 |
| 25 | 5500597632 |
| 26 | 7555866072 |
| 27 | 10253438688 |