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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 17 |
| 5 | 41 |
| 6 | 107 |
| 7 | 287 |
| 8 | 809 |
| 9 | 2341 |
| 10 | 6965 |
| 11 | 21101 |
| 12 | 65031 |
| 13 | 202939 |
| 14 | 640441 |
| 15 | 2039509 |
| 16 | 6546861 |
| 17 | 21158437 |
| 18 | 68791923 |
| 19 | 224839127 |
| 20 | 738316629 |
| 21 | 2434622357 |
| 22 | 8058616301 |
| 23 | 26765349429 |
| 24 | 89173526191 |
| 25 | 297942766331 |
| 26 | 998072479961 |
| 27 | 3351459203873 |