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 | 13 |
| 3 | 21 |
| 4 | 132 |
| 5 | 837 |
| 6 | 1373 |
| 7 | 8708 |
| 8 | 55229 |
| 9 | 90597 |
| 10 | 574596 |
| 11 | 3644277 |
| 12 | 5978029 |
| 13 | 37914628 |
| 14 | 240467053 |
| 15 | 394459317 |
| 16 | 2501790852 |
| 17 | 15867181221 |
| 18 | 26028336893 |
| 19 | 165080281604 |
| 20 | 1046993493533 |
| 21 | 1717475775621 |
| 22 | 10892796795012 |
| 23 | 69085703391957 |
| 24 | 113327372854093 |
| 25 | 718759508189188 |