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 | 1 |
| 1 | 6 |
| 2 | 1680 |
| 3 | 1235520 |
| 4 | 1764322560 |
| 5 | 4151586700800 |
| 6 | 14572069319808000 |
| 7 | 71382386874839040000 |
| 8 | 465322312113382563840000 |
| 9 | 3894941973875807210323968000 |
| 10 | 40716268141852504209197629440000 |
| 11 | 519879261146393786614332810854400000 |
| 12 | 7961721525959456256504412439642112000000 |