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 | 48 |
| 3 | 368 |
| 4 | 2304 |
| 5 | 12864 |
| 6 | 66816 |
| 7 | 330496 |
| 8 | 1579008 |
| 9 | 7353344 |
| 10 | 33583104 |
| 11 | 151056384 |
| 12 | 671219712 |
| 13 | 2953068544 |
| 14 | 12885491712 |
| 15 | 55835820032 |
| 16 | 240520790016 |
| 17 | 1030797656064 |
| 18 | 4398058045440 |
| 19 | 18691721789440 |
| 20 | 79164887531520 |
| 21 | 334251639701504 |
| 22 | 1407375101657088 |
| 23 | 5910974963908608 |