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 | 2 |
| 1 | 12 |
| 2 | 80 |
| 3 | 576 |
| 4 | 4352 |
| 5 | 33792 |
| 6 | 266240 |
| 7 | 2113536 |
| 8 | 16842752 |
| 9 | 134479872 |
| 10 | 1074790400 |
| 11 | 8594128896 |
| 12 | 68736253952 |
| 13 | 549822922752 |
| 14 | 4398314946560 |
| 15 | 35185445830656 |
| 16 | 281479271677952 |
| 17 | 2251816993554432 |
| 18 | 18014467228958720 |
| 19 | 144115462953762816 |