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 | 5 |
| 2 | 25 |
| 3 | 121 |
| 4 | 581 |
| 5 | 2776 |
| 6 | 13204 |
| 7 | 62535 |
| 8 | 294967 |
| 9 | 1385969 |
| 10 | 6488635 |
| 11 | 30273074 |
| 12 | 140779986 |
| 13 | 652648100 |
| 14 | 3016745162 |
| 15 | 13905372533 |
| 16 | 63924885355 |
| 17 | 293126854872 |
| 18 | 1340883359460 |
| 19 | 6119617278729 |
| 20 | 27867658231717 |
| 21 | 126637380509476 |
| 22 | 574312506857594 |