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 | 2 |
| 2 | 8 |
| 3 | 24 |
| 4 | 78 |
| 5 | 232 |
| 6 | 720 |
| 7 | 2152 |
| 8 | 6528 |
| 9 | 19578 |
| 10 | 58944 |
| 11 | 176808 |
| 12 | 531128 |
| 13 | 1593288 |
| 14 | 4781952 |
| 15 | 14345792 |
| 16 | 43043622 |
| 17 | 129130584 |
| 18 | 387411144 |
| 19 | 1162232520 |
| 20 | 3486755688 |
| 21 | 10460266224 |
| 22 | 31380972784 |
| 23 | 94142915640 |
| 24 | 282429275616 |
| 25 | 847287817866 |
| 26 | 2541865038832 |
| 27 | 7625595108432 |