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 | 4 |
| 2 | 14 |
| 3 | 48 |
| 4 | 166 |
| 5 | 584 |
| 6 | 2092 |
| 7 | 7616 |
| 8 | 28102 |
| 9 | 104824 |
| 10 | 394404 |
| 11 | 1494240 |
| 12 | 5692636 |
| 13 | 21785872 |
| 14 | 83688344 |
| 15 | 322494208 |
| 16 | 1246068806 |
| 17 | 4825743832 |
| 18 | 18726622964 |
| 19 | 72798509728 |
| 20 | 283443548276 |
| 21 | 1105144970992 |
| 22 | 4314388905704 |
| 23 | 16862208539008 |
| 24 | 65972020761116 |
| 25 | 258354647959984 |
| 26 | 1012627828868072 |