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 | 40 |
| 2 | 1040 |
| 3 | 22400 |
| 4 | 435456 |
| 5 | 7956480 |
| 6 | 139694080 |
| 7 | 2387968000 |
| 8 | 40075329536 |
| 9 | 663887544320 |
| 10 | 10896534405120 |
| 11 | 177653730508800 |
| 12 | 2882307270639616 |
| 13 | 46596186764738560 |
| 14 | 751299029274460160 |
| 15 | 12089975328525516800 |