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 | 3 |
| 2 | 6 |
| 3 | 12 |
| 4 | 26 |
| 5 | 62 |
| 6 | 158 |
| 7 | 418 |
| 8 | 1129 |
| 9 | 3087 |
| 10 | 8507 |
| 11 | 23573 |
| 12 | 65611 |
| 13 | 183333 |
| 14 | 514137 |
| 15 | 1446723 |
| 16 | 4083725 |
| 17 | 11560877 |
| 18 | 32816588 |
| 19 | 93385330 |
| 20 | 266360509 |
| 21 | 761373941 |
| 22 | 2180721568 |
| 23 | 6257750542 |
| 24 | 17988623409 |
| 25 | 51795127277 |
| 26 | 149363509694 |
| 27 | 431341949970 |