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 | 3 |
| 2 | 15 |
| 3 | 69 |
| 4 | 309 |
| 5 | 1365 |
| 6 | 5973 |
| 7 | 25941 |
| 8 | 112065 |
| 9 | 482067 |
| 10 | 2066583 |
| 11 | 8834469 |
| 12 | 37677603 |
| 13 | 160367343 |