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 | 16 |
| 3 | 50 |
| 4 | 130 |
| 5 | 310 |
| 6 | 736 |
| 7 | 1821 |
| 8 | 4673 |
| 9 | 12107 |
| 10 | 31103 |
| 11 | 79039 |
| 12 | 199819 |
| 13 | 505477 |
| 14 | 1282309 |
| 15 | 3259549 |
| 16 | 8288613 |
| 17 | 21064316 |
| 18 | 53497376 |
| 19 | 135833020 |
| 20 | 344914900 |
| 21 | 875983319 |
| 22 | 2224986219 |
| 23 | 5651490601 |
| 24 | 14354263713 |
| 25 | 36457137516 |
| 26 | 92593166734 |
| 27 | 235168023403 |