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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 96 |
| 6 | 576 |
| 7 | 4032 |
| 8 | 32256 |
| 9 | 290304 |
| 10 | 2612736 |
| 11 | 28740096 |
| 12 | 344881152 |
| 13 | 4483454976 |
| 14 | 62768369664 |
| 15 | 878757175296 |
| 16 | 14060114804736 |
| 17 | 239021951680512 |
| 18 | 4302395130249216 |
| 19 | 81745507474735104 |
| 20 | 1553164642019966976 |
| 21 | 32616457482419306496 |
| 22 | 717562064613224742912 |