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 | 6 |
| 2 | 28 |
| 3 | 120 |
| 4 | 496 |
| 5 | 672 |
| 6 | 8128 |
| 7 | 523776 |
| 8 | 33550336 |
| 9 | 459818240 |
| 10 | 1476304896 |
| 11 | 8589869056 |
| 12 | 14182439040 |
| 13 | 31998395520 |
| 14 | 51001180160 |
| 15 | 137438691328 |
| 16 | 518666803200 |
| 17 | 13661860101120 |
| 18 | 30823866178560 |
| 19 | 740344994887680 |
| 20 | 796928461056000 |
| 21 | 212517062615531520 |
| 22 | 2305843008139952128 |