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 | 1 |
| 2 | 4 |
| 3 | 33 |
| 4 | 480 |
| 5 | 11010 |
| 6 | 367560 |
| 7 | 16854390 |
| 8 | 1016930880 |
| 9 | 78124095000 |
| 10 | 7446314383200 |
| 11 | 862332613342200 |
| 12 | 119261328828364800 |
| 13 | 19415283189746043600 |
| 14 | 3675162134109650184000 |
| 15 | 800409618620667941886000 |
| 16 | 198730589981586780813696000 |
| 17 | 55800304882692417053710704000 |