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 | 12 |
| 3 | 48 |
| 4 | 188 |
| 5 | 740 |
| 6 | 2936 |
| 7 | 11672 |
| 8 | 46388 |
| 9 | 184352 |
| 10 | 732608 |
| 11 | 2911040 |
| 12 | 11565964 |
| 13 | 45949600 |
| 14 | 182538264 |
| 15 | 725108640 |
| 16 | 2880270032 |
| 17 | 11440564516 |
| 18 | 45441048384 |
| 19 | 180483666608 |
| 20 | 716832688844 |
| 21 | 2847012624636 |
| 22 | 11307166941460 |