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 | 0 |
| 6 | 90 |
| 7 | 630 |
| 8 | 3780 |
| 9 | 18900 |
| 10 | 94500 |
| 11 | 457380 |
| 12 | 3825360 |
| 13 | 31505760 |
| 14 | 312432120 |
| 15 | 2704501800 |
| 16 | 22984481520 |
| 17 | 179863997040 |
| 18 | 1531709328240 |
| 19 | 13078616488560 |
| 20 | 147223414987200 |
| 21 | 1657733805020160 |
| 22 | 20131890668255520 |
| 23 | 226464779237447520 |
| 24 | 2542924546378413120 |
| 25 | 27053572399079688000 |