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 | 5 |
| 2 | 17 |
| 3 | 69 |
| 4 | 277 |
| 5 | 1109 |
| 6 | 4437 |
| 7 | 17749 |
| 8 | 70997 |
| 9 | 283989 |
| 10 | 1135957 |
| 11 | 4543829 |
| 12 | 18175317 |
| 13 | 72701269 |
| 14 | 290805077 |
| 15 | 1163220309 |