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 | 4 |
| 2 | 16 |
| 3 | 40 |
| 4 | 160 |
| 5 | 280 |
| 6 | 2176 |
| 7 | 2800 |
| 8 | 17920 |
| 9 | 44224 |
| 10 | 263296 |
| 11 | 419872 |
| 12 | 4280320 |
| 13 | 5594000 |
| 14 | 44751616 |
| 15 | 134391040 |
| 16 | 539054080 |
| 17 | 1073758360 |
| 18 | 11453771776 |
| 19 | 15271054960 |
| 20 | 137575813120 |
| 21 | 366528038400 |
| 22 | 1759220283904 |
| 23 | 3198580043440 |
| 24 | 35193817661440 |
| 25 | 56294998751872 |